Medical Center Supply

 Home Up About Us Testimonials F. A. Q. Guidelines Price Guarantee  Troubleshooting Tips                  

  Home
Pride Lift Chair Parts
Golden Tech Parts
Med Lift Parts
La Z Boy Parts
Berkline Parts
Best Chair Parts
Hubbell Parts
Okin Parts
Dewert Parts
Hand Controls
Switches
Hardware
Troubleshooting Tips

 

It only makes sense that before you can repair a lift chair, you need to have a pretty good idea of what's wrong with it...  There are several ways to go about this (some better than others)... One method is just guess what part you need; sort of a "warm feeling"; Another method would be to ask someone you know for their opinion, maybe your neighbor's third cousin's fishing buddy... Those choices might work out, but most likely would lead to a lot of wasted time and frustration.  Or, you could spend a little time using an electrical meter, our notes on these pages, and a little common sense, and in most cases, have your chair back working again.  We developed the following section to help you with figuring out what may be wrong, and what needs to be done to repair your chair.  Please remember that this is only a guide, and is not intended to be the only solution, or even the correct solution, for every problem.  This is based on what we have learned in over eighteen years experience "in the real world" repairing lift chairs in our service area, and from feedback we have received from our customers across the country.     

In most cases, there is no need to call a technician in to repair a lift chair; the problems listed here can easily be completed in the home by almost anyone (please keep in mind that the last statement was made by a service technician that made his living by doing service calls...).  Even if you buy more parts than what you really need, it will still be cheaper than paying for a service call... We hope the information is helpful in your situation.

Although there are differences in the major manufacturers of power lift chair bases, the general principles of lift chair operation are the same.  They all use a lift motor to operate a lift mechanism mounted by scissor arms to the wooden chair frame.  Internal to the motor is an acme screw/worm gear system that pushes the chair to the lift position and pulls the chair to recline.  When the actuator is fully extended, the chair is in the full upright position; when the motor is fully retracted, the chair is in the fully reclined position.

This guide is broken down into three sections, based on what brand the motor and other electronics the chair has.  Knowing the manufacturer of the chair is helpful, and it is one of the first questions I usually ask, but even knowing that, we still need to know what electronics that manufacturer used when they built your chair.  For instance, Pride Mobility, the largest manufacturer of lift chairs in the USA, has at some point  used all three of the motor sets described below.  The motor information should be on a sticker on the side of the motor.  Turn the chair over on its side, see if you can find that information (you may have to stand on your head to see it...), then check below for the most common problems and possible solutions.

One other point, and then you can go to work; these tips were written for someone with general electrical knowledge and a good dose of common sense... The suggestions will be "way over the head" of some who attempt these checks, and it will be elementary and boring to others who have been diagnosing electrical problems for years... I wrote these as if I was coming into your home on a service call, with a small set of tools and gadgets to work with, and without the thousands of dollars of inventory I have at my shop that I could use to swap parts around to see what the problem is.  I realize that this section may fall under the "if all else fails, read the instructions..." category, but that is the concept anyway.

If, after reading the suggestions below, you still can't figure out what is wrong, or if you just don't want to deal with figuring out what the problem is, you can send the complete electrical system (motor, transformer, hand control, power cord) to us here in Mississippi, and because we are all-around nice guys, we will check it out for you free of charge; all you would pay is for the parts needed plus return shipping for the system.  Feel free to sent it down to us for checking, just please put a note in the box describing the problem you are having, and a contact number so we can call you with what we find (even if you have called before you sent it, I will have slept a night or two and will have forgotten what we talked about (I'm like a duck - it's a "new world every day"...)

A note about calling in for assistance:  I am hesitant to write this, but for my own sanity (or what's left of it...) I must say this, and I say it in the most gentle way that I can:  We have spent untold hours compiling these troubleshooting tips, and even more hours revising and adding to the notes below. Yet, every day, many times a day, someone will call in and ask a questions that is clearly explained in the steps below.  When I ask if they have gone through the steps in the troubleshooting section, the general response I get is "I saw all that, but I thought it would be easier to just call"... I have been doing this for a long time, and have gotten pretty good at it, but for the life of me, I can't be as good about finding what the problem is when I am 500 miles away as you can sitting next to the chair.  I say all that to say this:  please go through the troubleshooting steps below before you call in for help.  If, after you go through the section below,  you still can't figure out the problem, then let us know and we will be glad to help.

 

Trouble Shooting Guide for Hubbell Motors

NOTE: Hubbell Special Products discontinued operations in October, 2008, so there is a very limited number of repair parts available for motor repair.  In some ways, this makes diagnosis easier (that's me, always looking for the bright spot...);  You can still get the capacitor and limit switches, and now we - finally - have the gear sets available.  I note those below as we go through the typical symptoms.  But with these few exceptions, if your Hubbell system is having problems, you replace either the hand control or the motor assembly (or both, if you want to order them together and save over the single piece prices, or if the plug on your hand control cord is anything but the four prong connector we show on our part # 4210).

1. Nothing about the chair will work, and the motor makes no noise whatsoever.

The most common problem is that the chair is not connected to the electrical supply, or the electrical supply is not working due to a breaker, a fuse problem, or a loose wall outlet in the home. Make sure there is electrical current at the outlet (try plugging a working lamp into the outlet the chair is plugged into; if the lamp lights up, then wiggle the lamp plug in the outlet a little to make sure the lamp doesn't go out because of a short in the wall receptacle), and that the chair is connected to the outlet (don't roll your eyes at how stupid this sounds - you don't want to know the number of miles I have driven to a call, only to find that the chair wasn't plugged in, or that the wall plug was loose and not making contact...). 

If a Hubbell motor is getting power, and the hand control is good, it normally will do something; it will buzz, click,  or hum, or make some sort of noise...  If the motor makes no noise whatsoever when you push the hand control, then we need to check the motor for output power, and if power there, we will check the hand control:

a) Checking the motor for output power:

  1. Unplug the hand control from the motor cord, but leave the motor plugged into the wall..

  2. Using your multimeter set on AC volts setting, put a meter lead into one of the connections on the motor cord, and the other lead into one of the other connectors.  If you don't get 120 volts there, keep swapping the leads in different holes until you get a 120 volt reading (I can't tell you specifically which set of holes will give the 120 volt reading, as not all Hubbell motors are wired the same...)  If you don't get 120 volts in some combination, then the problem is in the motor somewhere... It could be as simple as a broken or shorted wire, or as complicated as a bad motor winding.  If you get 120 volts on your meter in one or more checks, then we check the hand control for a bad switch or bad wiring.

 

b)  Checking the hand control:

  1. Make sure the hand control is not plugged into the motor.

  2. Take the hand control apart; most controls have screws in the housing that you can unscrew; a few older ones have a "snap together" housing that you can pry apart with a small screwdriver; still other older controls have housings that are glued together so that you can't take them apart (in that case, replace the complete hand control).

  3. Check the switch:

     

     

    If you have a meter:

    1. Remove the screws from the back of the hand control and take the hand control apart, exposing the switch.

    2. Set meter to OHMS setting.

    3. Pull the wire (usually red but not always) off the middle tab on the switch.

    4. Put your RED meter lead on the middle tab on the switch.

    5. Put your BLACK meter lead on one of the other outer tabs.

    6. Press the switch in each direction;  a low reading in one of the directions (and only one) means the switch is operating properly

    7. Now, move the BLACK lead to the other outer tab and do the same test as # 6

    8. If you get a low reading on both tests, then the switch is OK.  If not, the replace the switch.

 

If you don't have a meter, you can do the following steps. 

HOWEVER, THE FOLLOWING TEST SHOULD ONLY BE ATTEMPTED BY QUALIFIED PERSONS FAMILIAR WITH ELECTRICITY AND COMFORTABLE WORKING AROUND LIVE POWER.  THIS TEST IS SIMILAR TO CHANGING A WALL RECEPTACLE WHILE THE POWER IS STILL ON; IF YOU WOULD NOT FEEL COMFORTABLE DOING THAT, DON'T DO THIS TEST:

  1. Remove the screws from the back of the hand control and take the hand control apart, exposing the switch.

  2. Make sure the chair is plugged into the wall and all wiring is hooked up.

  3. Take an insulated screwdriver (plastic, rubber or wooden handle) and touch the middle connector on the switch to one of the outside connectors (we call this "shorting" the switch); this should make the chair run in one direction.

  4. Then, take the insulated screwdriver (plastic, rubber or wooden handle) and touch the middle connector on the switch to the other outside connector; this should make the chair run in the other direction.

  5. If the chair runs in each direction with this test, then replace the switch; if the chair still won't run both ways, then the problem is NOT in the switch, so ordering a switch would do NO good (also, if you order a switch and hook the wires to it, then we can't take it back as it would leave marks on the tabs and would look make it look used...).

 

If the switch passes this test, then we need to check the continuity of the hand control wiring.

c)  Check the hand control wiring:

  1. Make sure the hand control is not plugged into the motor.

  2. Set meter to the OHMS setting.

  3. Put one lead on one of the wires of the switch, and the other lead on the same color wire at the end of the cord; a low reading means that wire is OK.  While the wires are connected, move the hand control cord around a little to see if the reading changes (which would indicate a short in that wire)

  4. Do the same test in 3 above to the other two wires.

  5. Any one of the wire tests that don't give you a reading on your meter means that the hand control should be replaced.

 

2. Chair is in the full lifted position and will not go down, or in the fully reclined position and will not come up.

Sometimes, the chair will go up but not back, or back but not up.  The user then keeps pushing the button on the way that it will go until the motor is fully extended, then the limit switch cuts the motor off, then it won't go either direction.  The most common cause of this is a defective switch or hand control; if the motor will run either direction, and it won't even try to run the other way, the motor is hardly ever the problem.

SOLUTION: Replace either the switch (if replaceable) or the hand control (after making sure that the chair is not connected to the electrical outlet).  Just follow the steps in symptom 1 above to check the switch and/or the hand control.

3. After the chair has run through several cycles of up and down the motor fails to work.

Normally, this means the thermal limit switch has overheated. This is a normal occurrence since this switch is designed to keep the motor from overheating to insure the life of the motor.

SOLUTION: Let the chair sit for 10 to 15 minutes, then the chair will begin to operate normally.

Note: This is one of the most frequent calls we receive from some dealers and a large number of consumers. For instance the grandchildren want to try out this new chair and they run the chair up and down, up and down, then the chair quits and we receive the call that their chair has just quit working (grandchildren are very good for our business...).

4. Chair will not lift or recline with a person sitting in the chair, but will lift and recline with no one in the chair.

PROBLEM: The most common cause for this is that the motor gears that are beginning to strip; they "hold" and work as long as the motor doesn't have to strain to work, but as weight is added to the chair, the gears fail.  Another not so common cause for this is a bad capacitor, or a weak capacitor;  check to see if the motor is abnormally hot (a good motor gets rather warm in normal operation, but if the motor housing gets "hot enough to fry an egg" hot, that is a sign of a weak capacitor. 

SOLUTION: If the motor is abnormally hot, you can try replacing the capacitor. Again, before making any repairs to the motor or electrical components, make sure the chair is not connected to electrical power.  Also, before touching the wires on the capacitor, take an insulated screwdriver (plastic, rubber or wooden handle) and touch the 2 connectors together while holding the insulated end of the screwdriver; sometimes, capacitors hold a "charge" in them even after the electrical current is unplugged.  If the motor is not abnormally hot, and you hear a grinding noise from the motor with weight on the chair, most likely the problem is in the motor gears (see question # 5 below).

5. Can hear the motor running, but there is no movement to the chair, or the chair runs a few seconds and stops again.

PROBLEM: This could be caused by two different items.

A. The gears might possibly be faulty in the motor (most common).

B. The motor push tube nut threads might be defective (less common). 

To test this out, you can do this:  first, lie the chair on the side, run the motor, and notice if the steel worm gear inside the round push tube is turning (you may have to take the motor out of the chair and hook the hand control back up to see this better; take the plastic cover off the outside of the round push tube (so you can see the worm screw better), hold the motor's push tube down on an old  piece of carpet to give some resistance, then run the hand control up and down.  If the worm gear does not turn when running the motor, then most likely you will have defective gears, or a shear pin defective in the gears.  If the worm gear is turning, then the gears are most likely good, but the nylon nut in the outer tube is defective.

SOLUT1ON: If the gears are defective (which is normally the case), you can either replace the gear set, or replace the motor assembly.  We now (finally) have the gear sets in stock for the Hubbell motors; we used to get them directly from the factory, but since it has now closed, we had find another source.  For anyone who has done tool and die or plastic fabrication work, you know that the molds for making the gears are very expensive, and two molds had to be made for this, doubling the cost.  That extra expense is being passed on to us in each set of gears that is made; that is why the cost is so high (before you call and ask…).   Gear installation instructions are farther down in this section, right after the motor timing and installation instructions.  You may want to weigh the cost of a set of gears against the price of a new motor with a six month warranty – the choice is entirely up to you.  If the push tube is defective, you will have to replace the complete motor, as the push tubes are not available anymore.  Our MS-1000 replacement motor is being used by one of the major chair manufacturers, and is a perfect fit for the Hubbell MC-42.

6. When being lifted, chair seems to sway from side to side. This is usually in rhythm with the motor.

Normally, this is caused by a bent or warped worm gear in the motor

SOLUTION: Replace the motor; since Hubbell went bankrupt, the worm gear isn't available anymore.

NOTE: This problem usually occurs when the chair has been dropped after moving.  I have also seen this happen if the grandkids have used the chair as a "jumping platform" (oh, to be young again...)

7. Chair seems to not sit level on the floor.

Usually a leveling guide is missing underneath the chair.

SOLUTION: Replace the missing glide, or put a shim on the low side under the chair.

8. Foot rest seems to be hanging on floor or is sitting unlevel when the chair is in a closed position.

Normally, that means the recline hardware is bent or broken.  There is a scissor mechanism on each side of the chair, attached to the footrest and the sides of the chair.  The easiest way to tell what's wrong is to turn the chair over on its side, and run the chair through a cycle and watch the mechanism move (you may have to put the chair on telephone books, etc so it won't push itself across the floor when it is running).  if the mechanism is bent, it will be obvious by watching it try to move.

SOLUTION: Replace the scissor mechanism.  We recommend replacing both sides of scissor mechanisms, even if only one side is bent or broken.  We would need to know the manufacturer of the chair, and the serial # to see if the mechanisms are available.

9. The motor in the chair seems to want to continue running after the chair has completed a lift or recline cycle. If you continue to engage the switch, the motor wants to continue to run. 

Oftentimes, this will cause the motor to "bind" itself, so you have to take the push tube loose and manually screw the tube in and out to free up the motor.  This is not a common problem, but it usually means one of the limit switches is defective.

SOLUTION: Replace the defective limit switch (after making sure chair is not connected to the electrical outlet).

10) The chair doesn't raise up or recline as far back as it used to, and in the other direction the chair bottoms out but the motor is still humming like it wants to run.

The motor timing is off; it "doesn't know when it's supposed to stop"...

SOLUTION: Retime the motor.  This often happens when changing a defective motor or if the timing gears are beginning to strip.  Motor timing and installation instructions are below.

11) You bought a new hand control from us, but your chair has an older motor plug that doesn't have a four prong connector, and you need to know how to install it.

The instructions below are slightly different, depending if you have a three prong connector that looks much like the standard four prong connector (round pins, with the two outside prongs having a flat spot so you can't plug it in wrong).  If you have one of the older connectors (four prong with flat pins, connector with orange terminals, or even a six prong square connector, etc), you will need to "hard wire" the hand control to your motor:

a)  Three prong connector:

If you ordered the #4210 with a three prong connector, we included the connector you need, along with the plastic housings that hold it into place.  However, because different manufacturers used different wiring methods back when these three prong connectors were in use, we couldn't insert the wires in the connector because we don't know what configuration is on your motor.  To do this, do the following steps:

  1. Plug your motor to an electrical outlet.

  2. Using your meter set on AC VOLTS, determine which of the wires on your motor plug is the hot, or "common" wire; this will be the one with the voltage reading.  The other two wires are directional wires (up and down).

  3. Unplug the motor from the wall outlet.

  4. Gently put the wire that goes to the middle wire on the switch on the new hand control to that common wire on the motor plug (on our new controls, that is the white wire, but that doesn't mean that it goes to the white wire on your motor).  Then put the other two wires to the other two connectors on the motor plug.

  5. Keeping the wires separated so they will not touch each other or yourself, plug the motor back into the electrical outlet and try the hand control to see if the motor runs as it is supposed to; if not, unplug the motor, reverse the last two wires you put in and try it again.

  6. When you know that you have the wires in the correct position on the plug, then firmly push the wires into the connector until they snap into place, hook the white plastic housings onto the plug, and screw the housings together with the two screws provided.

 

b)  Hard wiring the new hand control to the motor:

Older Hubbell motors used a variety of connectors to fasten the hand controls onto the motors; If you have one of the older connectors mentioned above, then you will need to "hard wire" the hand control to your motor.

  1. Plug your motor to an electrical outlet.

  2. Using your meter set on AC VOLTS, determine which of the wires on your motor plug is the hot, or "common" wire; this will be the one with the voltage reading.  The other two wires are directional wires (up and down).

  3. Unplug the motor from the wall outlet.

  4. Cut the plug off the motor where it would connect to the hand control, and strip about 3/8" of the insulation off the wires.

  5. Cut the plug off the end of the new hand control and strip about 3/8" of the insulation off those wires.

  6. Attach the wire that goes to the middle wire on the switch on the new hand control to that common wire on the motor plug (on our new controls, that is the white wire, but that doesn't mean that it goes to the white wire on your motor).  Then attach the other two wires to the other two connectors on the motor plug.

  7. Keeping the wires separated so they will not touch each other or yourself, plug the motor back into the electrical outlet and try the hand control to see if the motor runs as it is supposed to; if not, unplug the motor, reverse the last two wires you put in and try it again.

  8. When you know that you have the wires in the correct position, be sure the motor is unplugged, then use crimp connectors to attach the wires together as they are positioned.

  9. Use electrical tape to tape up all the wires together to better protect them from damage.  


MOTOR TIMING & INSTALLATION INSTRUCTIONS

The motor is a powerful electrical mechanism with up to 1000 lb torque; Injury or damage may occur if not properly handled and installed.  We have trained personnel who can assist you, so please don't hesitate to call if you have any trouble reinstalling the motor.

Motors are equipped with limit switches which allow the motor tube to run in and out only so far before stopping; we "time" the motor so these switches will operate correctly.

1) Lay the chair on its side.

2) If the motor is still on the chair, take the clevis pin out of the end of the push tube (C) (see illustration below) where it goes through the chair bracket.

3) Connect the motor base (A) (if not already connected)  to the base of the chair.

4) Plug in the motor, push the down button on the hand control, and let the motor run until it stops (note: do not have your hand on the push tube (C) while the motor is running at this step- just let it "free-wheel" until it stops running.  Some new motors are factory set in this position already, so the motor might not run when the down button is pushed; if so you can push the up button to make sure the motor has power, then the down button to get it in the right position.

5) Hand screw the push tube (C) down toward the motor housing until it bottoms out (you will have to feel for it bottoming out, as the dust cover is covering that space).  Then turn it back out two full turns; this will allow the 1/4" to 3/8" space (B) between the bottom of the tube and the hub of the motor that we need (if you like, you can take the dust cover off so you can measure the distance, but usually two full turns will give the proper clearance).

6) At this point, grab hold of the push tube (C) with one hand and push the up button on the hand control with the other hand; the push tube should start going out from the hub.  Take the tube out as far as is needed to align the tube with the connection on the chair.  Put the pin back in at the end of the tube (note: only run the motor up or down to align the components -   do not screw the tube in or out to do the alignment.  This will fully connect the motor.

7) Turn the chair back over and run it all the way up to make sure the limit switch turns the motor off when it is in the fully lifted position; then run the chair all the way down to the fully reclined position and see if the limit switch cuts it off there.  If the motor tries to keep running when the chair is all the way up or all the way reclined, the timing is still off; repeat the steps above or call for assistance.

 

Please Note: Listed below are the instructions for replacing the gears or push tube.  I could take the push tube instructions off the website, as the push tube isn't available for purchase anymore, but I will leave it on here, in case you are lucky enough to find another motor that you can take the push tube out of to repair your motor.

GEAR REMOVAL & INSTALLATION INSTRUCTIONS

This is not a hard job to do (especially if you have done it a few hundred times...), but it is one of the messier jobs you will do - I suggest wearing latex gloves and old clothes...

To Remove Gears:

  1. Remove the motor from the lift chair by pulling two clevis pins; one pin is located at the base of the motor and the other pin is located at the end of the screw tube.

  2. Sit the motor on a workbench or similar surface.  Cover the surface of the bench with newspapers, old sheets, etc to catch the grease that will invariably get all over everything...

  3. Remove the two screws from the outside of the round electrical cover that sits on top of the gear housing.

  4. Remove the six screws that hold the gear housing cover to the motor base

  5. Carefully fold the gear housing cover back over the top of the motor (there are wires that go through the cover, so you won't be able to take it completely off the motor).  CAUTION: Fold the cover back very carefully to keep from knocking the small timing gears (right side of picture below) out of position (if you do knock them off, call me and I will explain how they go back).

  6. Remove the output gear (B) (see illustration below).

  7. Remove the washers and bearings that are on the shaft end of the drive gear (A); NOTE: Pay attention to how the washers and bearings come off, so you can reinstall them the same way going back.  Also, look inside the housing cover - one or more of the washers and bearings may be imbedded in the grease there.

  8. Remove the round metal covering from around the roll pin (C); you may need to use a small blade screwdriver to work the covering from around the drive gear - sometimes, they are on tight (I get calls all the time from people saying that "their motor doesn't have a roll pin", because they don't have the metal cover off...)

  9. Use a 5/16" punch to knock out the roll pin in the drive gear (A); you may have to have someone hold the worm gear while you tap the roll pin out, so the gear and tube won't turn.

  10. Tap - gently - on the end of the worm gear until the drive gear (A) comes completely off.

 

To Reassemble Gears:

Reverse the top ten steps.  NOTE: It is OK to reuse the original roll pin (it doesn't have much torque on it, so there is little danger of breakage); also, it's also acceptable to reuse the old grease (the stuff that keeps trying to get on your clothes and work area... the factory uses plenty of grease when they assemble motors) around the new gears; just put it on like it was around the old gears.  If you would rather not do that, any standard gear grease from an auto parts house would work fine.

PUSH TUBE REMOVAL & INSTALLATION

When replacing the round push tube, the gears must be pulled off and the worm gear taken completely away from the motor.  The tube must have the steel worm gear started through from the unthreaded end (see illustration).

 

Trouble Shooting Guide for Okin Motors

 

More lift chair manufacturers use the Okin electronics system than any other system today, mainly because they are quiet running and, usually, very dependable.  There are four components to a standard Okin system, and we will mention all of them in the symptoms mentioned below; they are, in order of the amount of problems experienced:

1) Hand control:  The hand control is by far the part that we sell the most... Okin hand controls have a circuit board built into them (why, I don't know, except that's the way the West German engineers designed the system); we could get into a long discussion as to what the circuit board does, but we don't really need to know (and besides, very technical electronics explanations just give me a headache...).  The problem is that as the hand control is used  - and abused (that is, it is dropped, sat on, water spilled into it, chair let down on it, etc), the solder contacts loosen, and the control usually starts working intermittently, and at some point it quits altogether...

2) Transformer:  This is the Okin part that we have the second most problems with.  It's not that they are abused that much (except when liquids get spilled into them or it somehow gets under the chair and the chair comes down on it...), but the fact is that it is operating 24/7, and nothing lasts forever (at least, nothing that I own)...  A simple check you can do is to feel the transformer to see if it is warm.  It should be warm, but not so hot that you don't want to hold onto it; if it is that hot, it needs to be replaced, no matter if it is still working or not - house fires are really inconvenient...  If the chair won't do anything, and the transformer is cold to the touch (assuming it has been plugged in for awhile), that well may be the problem.

3) Motor:  Many people that call in say that their chair isn't working, and they think the motor is out.  In fact, I spend a great deal of my days talking people out of ordering new motors... It's sort of like if you come into your house in mid-summer and the house is hot; you automatically assume the compressor is out; many times (unless you have my luck...) that's not the case.  In fact, the motor is one of the last things I suspect in a lift chair problem... Usually, if a defective motor is the problem, it will be pretty obvious; the motor will smoke, or it will run but not pick up the chair, or you can hear gears grinding, etc.  The motor is hardly ever the problem if it is just dead silent and not making any noise at all...

4) Power Cord: Unless the cord has obvious damage (which does happen, as a loose cord can easily get caught in the chair mechanism when it moves), cords hardly ever cause any problem... In 18 years, I can count on two hands how many power cords I have found that were bad without showing any external damage... 

 

1)  Nothing about the chair will work.

The most common problem is that the chair is not connected to the electrical supply, or the electrical supply is not working due to a breaker, a fuse problem, or a loose wall outlet in the home. Make sure there is electrical current at the outlet (try plugging a working lamp into the outlet the chair is plugged into; if the lamp lights up, then wiggle the lamp plug in the outlet a little to make sure the lamp doesn't go out because of a short in the wall receptacle), and that the chair is connected to the outlet (don't roll your eyes at how stupid this sounds - you don't want to know the number of miles I have driven to a call, only to find that the chair wasn't plugged in, or that the wall plug was loose and not making contact...). 

If the power is OK, then the first step is to check the transformer:

a) Check Transformer/Motor Power Lead:

  1. Turn the chair on its side and find the leads coming from the motor housing

  2. At the motor, disconnect the small two prong wire coming from the transformer.

  3. Plug the chair into the wall, if not already done (unlike the Hubbell system above, the Okin motor is a low volt system, greatly minimizing the danger of electrical shock).

  4. Set your multimeter to the DC Volts setting, put your RED lead into the SMALLER of the two openings on the cord; you will probably have to put a paper clip or pin into the holes, then put your lead onto that; (I don't understand why they made the contact points so small, but then again, they didn't ask me...), then your BLACK meter lead into the LARGER opening.  Your meter should read from 24 -38 volts DC current.  If you get a reading, then both the transformer and power cord are OK.

  5. If you get no current reading, then unplug the wire lead coming out the end of the transformer, and do the same check described above directly at the transformer end connector.  If you get a voltage reading there, then the power cord from the transformer to the motor is defective.  If no voltage reading, then the transformer is defective.

 

If there is power going to the motor, then checking the hand control is the next step:

 

 b) Check the Hand Control:

 

Note: The following procedure is very difficult to do by yourself with your own two hands; it is very hard to hold the plug with one hand, and your two meter leads with the other, and get both the leads on those small pins without it touching the adjacent pins and giving a false reading.  Either having another person hold the plug for you, or putting the plug in a vise or some other holding device helps greatly...

  1. Unplug the chair from the power source.

  2. Disconnect the hand control lead from the motor connector.

  3. Set your multimeter to the OHMS setting.
     


     

  4. Using the diagram above, place the RED multimeter lead on PIN 1 of the hand control cord.

  5. Place the BLACK lead on PIN 2.

  6. Press the switch to the DOWN position.  A low reading means the hand control is operating properly in the "recline" position.

  7. Move the BLACK lead to PIN 3.

  8. Press the switch to the UP position.  A low reading means the hand control is operating properly in the "lift" position.

  9. If either test fails, replace the hand control.

 

Another note: With a hand control that is working intermittently, it is possible that you could get a good reading if everything is lined up correctly, but if you move the cord around a little, the test will fail.  If you can, have someone wiggle the hand control housing and cord while you take the reading.  If the reading fails then, replace the hand control.

 

Most of the time, you will find that the hand control is the problem.  In fact, if all this is confusing, and you just want to try the "warm feeling" method of repair, try ordering a hand control; most of the time, you will be correct... We have an inside joke around the shop here when customers send in their parts for us to check: "It's always the hand control..."  It isn't, of course, but it sure seems that way...

 

c) Check the motor:

  1. Unplug the chair from the power source.

  2. At the motor, disconnect the small two prong wire coming from the transformer.

  3. Set your multimeter to the OHMS setting.

  4. Place one lead on each pin coming from the motor.

  5. If less than one (1) ohm is read on the meter (in other words, if you have a digital meter, and the reading ever changes), then consider replacing the motor.

 

Note: Please refer to the notes about the motor above... I have seen a great many Okin motors that checked OK with the test above (that is, it tested to the 1 ohm reading) but the motor was bad...  In reality, there is no really good electrical test that will definitely show a bad motor.  The best thing to do (if you don't have a known good part to test with) is to eliminate everything else in the system, and if you are fairly sure that everything else is OK, then try replacing the motor. IMPORTANT: When you receive the new motor, try it by plugging the wires into the motor without mounting the motor in the chair; we can't take the motor back if it has been installed in the chair, as it would show use, and no one else wants to buy a used motor...

 

Another Note: An Okin motor cannot be checked by applying voltage directly to the motor power leads... There is a circuit board in the hand control, and also another in the Okin motor that keeps direct voltage from running the motor... This can be done with Dewert motors, but not with Okin...

 

A Final Note:  I want to repeat and re-emphasize what I said earlier in the component section above:  Most people automatically think that if their chair isn't working, they just know that  the motor is out.  As I said earlier, I spend a great deal of my day talking people out of ordering new motors...   In fact, the motor is one of the last things I suspect in a lift chair problem... Usually, if a defective motor is the problem, it will be pretty obvious; the motor will smoke, or it will run but not pick up the chair, or you can hear gears grinding, etc.  The motor is hardly ever the problem if it is just dead silent and not making any noise at all...  Don't get me wrong: motors do go bad, it's just not nearly as common as most people think.

 

2)  The chair will raise up but not recline, or will recline but won't raise (in other words, the chair will run one way but not the other).

The cause of this in an Okin system is almost always a defective hand control.  The reason is that in an Okin system, power is continually going to the motor from the transformer; if the chair runs one way but not the other, that means the transformer and the power cord from the transformer to the motor are both good (if they weren't, the motor would not move at all).  Okin motors almost never go bad when they will work one direction but not the other; in fact, I can't remember the last time I heard of an Okin motor that did that... The only other component to the Okin system is the hand control, and as mentioned above, is the part that causes the most trouble...

3)  The chair will raise up to a standing position OK, and it goes back down to a sitting position OK, but when the chair gets to the point that the footrest should extend and the back recline, the chair stops moving, and you hear a grinding or squeaking noise.

This is usually caused by a broken spindle nut inside the actuator (our part #6258).  As mentioned in the introduction above, a lift chair motor pushes the chair to the lift position and pulls the chair to recline.  If the spindle nut is cracked or broken, it holds together to push the chair up; the weight of the operator helps to take the chair to the sitting position.  But when the chair goes back any further, the spindle nut has to pull to get the chair to recline; if the nut is damaged, it can't do that...  To tell for sure, do the following test:

a)  Checking the spindle nut:

  1. Run the chair to the standing position, then push the down button to get the chair back to the sitting position.  Hold the down button to get the chair into the recline position, until the footrest stops going out and the chair stops going back and the problem starts

  2. Then, turn the chair on its side, and take the clevis pin out of the end of the stroke tube, so that end of the motor is now detached from the chair.

  3. Now, check to see if the stroke tube (the long round shaft that goes in and out of the motor) is loose inside the actuator tube; In a normal motor, you would have to unscrew the tube out of the motor (the tube has left hand threads)... A motor with a broken spindle nut will be loose inside the housing; usually, you can simply pull it out of the housing without unscrewing.  Replace the spindle nut, and all should be well again.

 

INSTALLATION INSTRUCTIONS FOR OKIN SPINDLE NUT

 Thank you for your purchase of the replacement spindle nut for your Okin Deltadrive  motor.  This new spindle nut should make the motor work as it was when new, but it must be installed correctly in order to function properly.  There are several different ways to install the nut, but we have found that following the steps below are the fastest and easiest: 

  1. Remove the plastic cap on the end of the outer aluminum tube by removing the two Phillips screws.
  2. Shine a flashlight into the end of the outer tube; you will find a small limit switch on the top end of the shaft that has two wires soldered to connections on the switch.
  3. Take a small paper clip, and straighten it out except for a bend in one end of the clip.  Put the paper clip (with the bend end first) in the shaft by the limit switch, hooking the wire furthest from you with the bend of the clip.  Then, use the body of the paper clip to touch the other wire connector on the switch; in effect, you are "shorting" the switch out with the paper clip.
  4. While holding the paper clip in place, push the "up" button on the hand control; if the paper clip is positioned correctly, the rest of the old spindle nut should move past the limit switch and off the end of the shaft.  If the nut stops when hitting the limit switch, then the paper clip is not positioned correctly.  Push the "down" button to back off the block, reposition the paper clip to ensure that the clip is touching both connections on the switch, and push the "up" button again.  When you have the paper clip positioned correctly, the rest of that old nut will "walk itself" off the end of the shaft.
  5. To install the new spindle nut in the motor, you don't have to use the paper clip anymore; position the new nut as it should go on the end of the worm screw, aligning the six "tabs" with the grooves in the outer tube, make sure that the steel worm screw is hitting the threads on the nut (the worm screw will drop down a little after the old nut is off), and push the "down" button on the hand control, and the new nut should "walk itself" on the motor.
  6. Reinstall the plastic cap on the end of the outer tube, screw the stroke tube down all the way on the spindle nut (remember to screw it counter-clockwise to tighten it), and you are done.

 

If the spindle nut is OK, the problem may be a bent scissor mechanism or damaged framework under the chair.  Please do the following:

b)  Check for scissor or frame damage:

Turn the chair on its side,  Examine the entire base of the chair for bends or breaks.  Check the scissor mechanisms for excessive wear or broken welds.  Examine the wood and the lift frame near the scissors for scrapes or damage; The problem may lie with those instead of the scissors.  Check the end of the motor lift tube, where it bolts to the chair; until very recently, they were made of a composite plastic (our part # 6250) , and often was the "weak point" of the motor assembly.  You you can't tell if the noise is coming from the chair frame or the motor, try removing the motor from the chair and manually move the chair to its various positions; sometimes you can find the squeak easier that way.  You can also run the motor while it is off the chair; if you hear loud noises from the motor that way, then the motor needs replacing.

4)  The chair is suddenly running very slowly, and sometimes won't work at all if someone is stilling in the chair.

It could be that the transformer is not working correctly with the household current, and it is now trying to work off the emergency battery backup.  In certain conditions, the transformer won't run on standard 120 volt power, but will still run off the batteries. To test this, do the following:

  1. Replace the two 9 volt batteries in the transformer with new batteries.

  2. Try running the chair without anyone sitting in the chair; see if the chair is running up and down, even if it still runs slower than normal.

  3. Now, with the chair still plugged into the wall receptacle, unplug the two 9 volt batteries

  4. Try running the chair again; if it doesn't run this time, then the transformer is defective and must be replaced.

 

5)  The battery backup system is not working.

The batteries may be dead, or battery leads may be damaged.

SOLUTION: Batteries need to be changed every 6 months (a good idea is to do this when you change your smoke detector batteries), or after every time they are activated due to power failure (the batteries only have enough power to run the chair for a cycle or two, then they will be dead).  If, after you change the batteries, the backup system still doesn't work, examine the battery leads for breaks, cracks, etc.  You can try replacing  the battery connectors If you have the room; if not, replace the transformer, if the battery backup is important to you (probably 90% of chairs with this feature don't have any batteries installed, or the batteries are dead, but manufacturers know that it is a good selling point, so they still use them).

 

INSTALLATION INSTRUCTIONS FOR OKIN MOVING BLOCK

 Thank you for your purchase of the replacement moving block for your Okin Betadrive  motor.  This moving block should make the motor work as it was when new, but it must be installed correctly in order to function properly.  There are several different ways to install the block, but we have found that following the steps below are the fastest and easiest: 

  1. Remove the plastic cap on the end of the aluminum shaft by removing the two Phillips screws.
  2. Shine a flashlight into the end of the shaft; you will find a small limit switch on the top end of the shaft that has two wires soldered to connections on the switch.
  3. Take a small paper clip, and straighten it out except for a bend in one end of the clip.  Put the paper clip (with the bend end first) in the shaft by the limit switch, hooking the wire furthest from you with the bend of the clip.  Then, use the body of the paper clip to touch the other wire connector on the switch; in effect, you are "shorting" the switch out with the paper clip.
  4. While holding the paper clip in place, push the "up" button on the hand control; if the paper clip is positioned correctly, the rest of the old moving block should move past the limit switch and off the end of the shaft.  If the block stops when hitting the limit switch, then the paper clip is not positioned correctly.  Push the "down" button to back off the block, reposition the paper clip to ensure that the clip is touching both connections on the switch, and push the "up" button again.  When you have the paper clip positioned correctly, the rest of that old block will "walk itself" off the end of the shaft.
  5. When the old block is off the shaft, IT IS VERY IMPORTANT to shine a light down the length of the opening on the shaft to be sure that all the little plastic parts of that old block are out of the aluminum shaft; if you leave any little parts of that old block in the shaft housing, then the new block will lock up when it is installed.
  6. To install the new block on the motor, you don't have to use the paper clip anymore; position the new block as it should go upon the end of the shaft, make sure that the steel worm screw is hitting the threads on the block (the worm screw will drop down a little after the old block is off), and push the "down" button on the hand control, and the new block should "walk itself" on the motor.
  7. Reinstall the plastic cap on the end of the shaft, and you are done.

 

 

 Trouble Shooting Guide for Dewert Motors

 

Dewert electronics are not as common as Okin systems, as they are mainly used by one manufacturer (Pride) in the USA.  However, Pride is the largest lift chair manufacturer in the USA, so there are hundreds of thousands of chairs in use with the Dewert system.  There are four components to a newer Dewert system, and even less in an older Dewert MB1 system.  We will mention all of them in the symptoms mentioned below; they are, in order of the amount of problems experienced:

1) Hand control:  The hand control is by far the part that we sell the most... Most Dewert hand controls are operated by a paddle switch; they don't have a circuit board built into them like the Okin controls do.  The only real significance of this is that on most Dewert controls, the switch can be replaced (see symptoms below).  The problem is that as the hand control is used  - and abused (that is, it is dropped, sat on, water spilled into it, chair let down on it, etc), the switch fails, or shorts develop in the hand control wiring, and the control usually starts working intermittently, and at some point it quits altogether...

2) Transformer:  This is the Dewert part that we have the second most problems with.  It's not that they are abused that much (except when liquids get spilled into them or it somehow gets under the chair and the chair comes down on it...), but the fact is that it is operating 24/7, and nothing lasts forever (at least, nothing that I own)...  There are two styles of Dewert transformers; older model Dewert systems like the MB1 have what we call an "internal" transformer (the transformer is mounted on the motor assembly under the chair).  Newer model chairs have an "external" transformer (the transformer sits behind the chair with a power cord connecting the transformer to the hand control and motor).  We will discuss troubleshooting both types in the symptoms below.

3) Motor:  Many people that call in say that their chair isn't working, and they think the motor is out.  It's sort of like if you come into your house in mid-summer and the house is hot; you automatically assume the compressor is out; many times (unless you have my luck...) that's not the case.  In fact, the motor is one of the last things I suspect in a lift chair problem... Usually, if a defective motor is the problem, it will be pretty obvious; the motor will smoke, or it will run but not pick up the chair, or you can hear gears grinding, etc.   The motor is hardly ever the problem if it is just dead silent and not making any noise at all (although Dewert motors seem to go out more often than Okin motors this way...)

4) Power Cord: Unless the cord has obvious damage (which does happen, as a loose cord can easily get caught in the chair mechanism when it moves), cords hardly ever cause any problem... In 18 years, I can count on two hands how many power cords I have found that were bad without showing any external damage... 

1)  Nothing about the chair will work.

The most common problem is that the chair is not connected to electrical supply, or the electrical supply is not working due to a breaker, a fuse problem, or a loose wall outlet in the home.  Make sure there is electrical current at the outlet (try plugging a working lamp into the outlet the chair is plugged into; if the lamp lights up, then wiggle the lamp plug in the outlet a little to make sure the lamp doesn't go out because of a short in the wall receptacle), and that the chair is connected to the outlet (don't roll your eyes at how stupid this sounds - you don't want to know the number of miles I have driven to a call, only to find that the chair wasn't plugged in, or that the wall plug was loose and not making contact...). 

If the power is OK, most likely the problem is in either the transformer or the hand control... As mentioned above, the power cord hardly ever gives any trouble, and the motor is usually the last thing to go out in the chair.  There are several ways to go about testing these components; I guess you could say there is a test for all "skill levels"; I will describe them below:

a) Easiest to do, but the least accurate:

  1. Make sure the transformer's power cord is connected to the wall, and that the hand control is plugged in.  A quick check you can do (especially if you don't have any test equipment to work with) is to check the transformer after it has been plugged in for at least an hour and feel the bottom of the transformer to see if it is warm.  It should be warm, but not so hot that you don't want to hold onto it; if it is that hot, it needs to be replaced, no matter if it is still working or not - house fires are really inconvenient...  If the chair won't do anything, and the transformer is cold to the touch (assuming it has been plugged in for awhile), that means the coil is bad inside the transformer, so the transformer should be replaced.  If it is warm to the touch, continue on with the next step...

  2. If you have the older style MB1transformer that is attached to the motor, then turn the chair over on its side so you can get your ear close to the transformer; if you have the newer style external transformer that sits behind the chair, move it around so you can get your ear close to it.

  3. With everything hooked up, push the switch on the hand control whichever way the chair won't go. and listen for a "click" in the transformer (you will hear a little click in the hand control switch, but the click in the transformer will be much louder)

  4. If you don't hear a click in the transformer, the problem is most likely in the hand control (either the switch or the hand control wiring); if you do hear a click in the transformer both directions, then the problem is most likely in the transformer.  The theory behind this is that if you don't hear the click in the transformer, this means that power is not getting through the hand control back to the relays in the transformer - the click you hear is the relays engaging...  If you don't hear the click, you can check out the switch and/or the hand control wiring using the steps farther down in this section.  If you do hear a click both directions, then odds are that the transformer is the problem.

  5. This test is around 75% accurate (sort of like a 75% chance of rain - most of the time it will rain, but sometimes not)... I have checked a good many systems where you can hear the click in the transformer, and it ended up being the hand control anyway.  Also, if you hear the click in the transformer, it could be working as it should, and the problem is in the motor itself.  That doesn't happen often, but the Dewert motors do go out from time to time without making a sound...

 

b)  Little harder to do, but more accurate:

  1. In this test, we are going to eliminate the hand control from the system and see what happens...

  2. If you have the older style MB1 transformer that is attached to the motor, then turn the chair over on its side so you can more easily get to the transformer.  If you have the newer style external transformer that sits behind the chair, the easiest thing way to do this is to take the motor out of the chair; just turn the chair over on its side, pull the clevis pins out of each end of the motor, and take the motor out.  Then, unplug the dual headed connector cable coming from the chair out of the transformer, and plug the motor directly into the transformer.

  3. Now, get two paper clips and straighten them out.

  4. Turn the transformer so that it looks like the picture above.  Carefully, put one paper clip in the hole on the five pin plug on the far right (pin #5 counting from the left); Then, carefully put the other paper clip in the hole just to the left of the hole that the other paper clip is in (pin #4 counting from the left).

  5. Carefully (there's that word again) touch the paper clips together... The round tube should retract in (if the motor tube is all the way in already, all you will hear is a click from the transformer)

  6. Leave the paper clip in the far right hole in, and take the other clip out and move it to the middle hole on the plug (pin # 3 counting from the left).

  7. Carefully touch the paper clips together... The round tube should extend out (if the motor tube is all the way out already, all you will hear is a click from the transformer).

  8. If the motor moves both ways with these tests, it confirms that both the transformer and motor are OK; this makes it almost certain that the problem is in the hand control; you can check out the switch and/or the hand control wiring using the steps farther down in this section.

 

c)  Still harder to do, but the most accurate:

These steps involve a good deal of work with electrical test equipment to check the various components of the electrical system.  These tests isolate each component to see if they pass or fail; following these steps closely, you should be fairly certain (or, as certain as you can be in lift chair repair..) to isolate the problem with the chair.

bullet

Check the Transformer:  As mentioned above, there are two styles of Dewert transformers; older model Dewert systems like the MB1 have what we call an "internal" transformer (the transformer is mounted on the motor assembly under the chair).  Newer model chairs have an "external" transformer (the transformer sits behind the chair with a power cord connecting the transformer to the hand control and motor).  To find which one you have, simply follow the power cord from the wall - whatever the cord is attached to is the transformer...

 

                Internal (MB1) Transformer System - Transformer mounted to the motor

  1. Turn the chair on its side and find the connections on the transformer that is strapped to the motor.

  2. Unplug the hand control from the control box.

  3. Plug the chair into the wall, if not already done (unlike the Hubbell system above, the Dewert motor is a low volt system, greatly minimizing the danger of electrical shock).

     

  4. Turn the transformer so that it looks like the picture above.  Set your multimeter to the DC Volts setting, put your RED lead onto the hole on five pin plug on the far right (pin # 5 counting from the left); (you will probably have to put a paper clip or pin into the holes, then put your lead onto that; I don't understand why they made the contact points so small, but then again, they didn't ask me...), then your BLACK meter lead onto the hole just to the left of the hole that the red lead is in (pin # 4 counting from the left).  Your meter should read 30-38 Volts DC. 

  5. Next, move the BLACK lead from the hole it is in to the middle hole on the plug (pin # 3 counting from the left).  Your meter should read 30-38 Volts DC. 

  6. If you don't get those readings, then replace the transformer (The internal transformers aren't available anymore, so you will need to order both our part #8230 transformer and #8264 Y connector cable).

 

 

                External (MBZ) Transformer System - Transformer Sits Behind the Chair

  1. Locate the transformer sitting behind or beside the chair.

  2. Unplug the dual headed "Mickey Mouse" plug coming from the chair that plugs into the transformer.

  3. Plug the transformer into the wall, if not already done (unlike the Hubbell system above, the Dewert motor is a low volt system, greatly minimizing the danger of electrical shock).

     

  4. Turn the transformer so that it looks like the picture above.  Set your multimeter to the DC Volts setting, put your RED lead onto the hole on five pin plug on the far right (pin # 5 counting from the left); (you will probably have to put a paper clip or pin into the holes, then put your lead onto that; I don't understand why they made the contact points so small, but then again, they didn't ask me...), then your BLACK meter lead onto the hole just to the left of the hole that the red lead is in (pin # 4 counting from the left).  Your meter should read 30-38 Volts DC. 

  5. Next, move the BLACK lead from the hole it is in to the middle hole on the plug (pin # 3 counting from the left).  Your meter should read 30-38 Volts DC. 

  6. If you don't get those readings, then replace the transformer.

 

If the transformer passes these tests, then the next step is to check the hand control.

 

bullet

Check the Hand Control Wiring:

 

Note: The following procedure is very difficult to do by yourself with your own two hands; it is very hard to hold the plug with one hand, and your two meter leads with the other, and get both the leads on those small pins without it touching the adjacent pins and giving a false reading.  Either having another person hold the plug for you, or putting the plug in a vise or some other holding device helps greatly...

  1. Unplug the chair from the power source.

  2. Disconnect the hand control lead from the transformer (if not already disconnected from the previous step).

  3. Set your multimeter to the OHMS setting.
     


     

  4. Using the diagram above, place the RED multimeter lead on PIN 1 of the hand control cord.

  5. Place the BLACK lead on PIN 2.

  6. Press the switch to the DOWN position.  A low reading means the hand control is operating properly in the "recline" position.

  7. Move the BLACK lead to PIN 3.

  8. Press the switch to the UP position.  A low reading means the hand control is operating properly in the "lift" position.

  9. If either test fails, replace the switch (if replaceable) or the hand control.

 
bullet

Check the switch:

 

 

When folks are having lift chair problems, they automatically think its either the motor or the switch.  While (as I explained above) it is very seldom that the motor is the problem, it is oftentimes due to a bad switch.  Thankfully, switches are very easy to check, and the following test should be done by everyone before they order a switch from us:

If you have a meter:

  1. Remove the screws from the back of the hand control and take the hand control apart, exposing the switch.

  2. Set meter to OHMS setting.

  3. Pull the wire (usually red but not always) off the middle tab on the switch.

  4. Put your RED meter lead on the middle tab on the switch.

  5. Put your BLACK meter lead on one of the other outer tabs.

  6. Press the switch in each direction;  a low reading in one of the directions (and only one) means the switch is operating properly

  7. Now, move the BLACK lead to the other outer tab and do the same test as # 6

  8. If you get a low reading on both tests, then the switch is OK.  If not, the replace the switch.

 

If you don't have a meter:

  1. Remove the screws from the back of the hand control and take the hand control apart, exposing the switch.

  2. Make sure the chair is plugged into the wall and all wiring is hooked up.

  3. Take an insulated screwdriver (plastic, rubber or wooden handle) and touch the middle connector on the switch to one of the outside connectors (we call this "shorting" the switch); this should make the chair run in one direction.

  4. Then, take the insulated screwdriver (plastic, rubber or wooden handle) and touch the middle connector on the switch to the other outside connector; this should make the chair run in the other direction.

  5. If the chair runs in each direction with this test, then replace the switch; if the chair still won't run both ways, then the problem is NOT in the switch, so ordering a switch would do NO good (also, if you order a switch and hook the wires to it, then we can't take it back as it would leave marks on the tabs and would look make it look used...).

 

bullet

Check the Motor:

   

       a)   Resistance Method:

  1. Unplug the chair from the power source.

  2. At the motor, disconnect the small two prong wire coming from the transformer.

  3. Set your multimeter to the MILLIOHMS setting.

  4. Place the BLACK lead on the LARGE pin, and the RED lead on the SMALL pin.

  5. The meter reading should show resistance in the 1.5 to 2.5 milliohm range.  If less than one (1) milliohm is read on the meter, replace the motor.

 

       b)   Transformer Output Method:

 

  1. If the transformer and hand control both pass your tests, then we need to take an output reading from the transformer.

  2. Make sure all wires and components are hooked up correctly.

  3. Unplug the motor from the transformer (if you have the internal transformer system where the transformer is mounted to the chair) or from the connector cable (if you have the newer external transformer system where the transformer sits behind the chair.

  4. Set your multimeter to the DC Volt setting.

  5. Put your meter leads in the female connector that the motor was just unplugged from in # 3 above.

  6. Push the UP button on the hand control; the meter should read 30-38 Volts DC

  7. Push the DOWN button on the hand control; the meter should read MINUS 30-38 Volts DC

  8. If you get both these readings, then the rest of the system is giving the correct voltage to the motor, and the motor is not running, so the motor should be replaced.

 

       c)    Direct Voltage Method:

 

A Dewert motor can also be checked by applying voltage directly to the motor.  You can take a 12 volt battery, or two 9 volt batteries wired in series, and put voltage directly to the motor terminals.  The large pin is the ground on the motor, an the smaller pin is the hot lead.  Positive voltage will make the motor push tube extend, and negative voltage will make it retract.  NOTE: this is less voltage than the motor is designed for, so don't run the motor but just a few seconds to see if it is operable or not.

 

Note: Please refer to the notes about the motor above... I have seen a great many Dewert motors that checked OK with the test above, but the motor was bad...  In reality, there is no really good electrical test that will definitely show a bad motor.  The best thing to do (if you don't have a known good part to test with) is to eliminate everything else in the system, and if you are fairly sure that everything else is OK, then try replacing the motor. IMPORTANT: When you receive the new motor, try it by plugging the wires into the motor without mounting the motor in the chair; we can't take the motor back if it has been installed in the chair...

 

 

2)  The chair will raise up but not recline, or will recline but won't raise (in other words, the chair will run one way but not the other).

This is more difficult to diagnose in a Dewert system than in the Okin system above; in the Okin system, power is given to the motor continually, so in that system, if the chair will run at all, then the transformer and power cord are OK.  In the Dewert  system, power isn't given to the motor until the switch is depressed... in each direction, power has to complete the circuit through the hand control, and then the relay has to energize to send power to the motor.  If there is a problem in either side of that system (up or down), the chair can run in one direction and be completely dead in the other... 

The only real difference between this symptom and the "nothing about the chair will work" discussion above is that there is almost no chance that the motor assembly is the problem... I don't know that I have ever seen a Dewert motor that would run one direction but not the other... Also, there couldn't be a problem with the household electrical power supply.  Other than that, the checks should be the same as #1 above; please go to symptom #1 above and look there and follow the steps to check out your system.

 

 

3)  The chair will raise up to a standing position OK, and it goes back down to a sitting position OK, but when the chair gets to the point that the footrest should extend and the back recline, the chair stops moving, and you hear a grinding or squeaking noise.

This is usually caused by a broken spindle nut inside the actuator (our part #8248).  As mentioned in the introduction above, a lift chair motor pushes the chair to the lift position and pulls the chair to recline.  If the spindle nut is cracked or broken, it holds together to push the chair up; the weight of the operator helps to take the chair to the sitting position.  But when the chair goes back any further, the spindle nut has to pull to get the chair to recline; if the nut is damaged, it can't do that...  To tell for sure, do the following test:

a)  Checking the spindle nut:

  1. Run the chair to the standing position, then push the down button to get the chair back to the sitting position.  Hold the down button to get the chair into the recline position, until the footrest stops going out and the chair stops going back and the problem starts

  2. Then, turn the chair on its side, and take the clevis pin out of the end of the stroke tube, so that the end of the motor is now detached from the chair.

  3. Check to see if the stroke tube (the long round shaft that goes in and out of the motor) is loose inside the actuator tube; In a normal motor, you would have to unscrew the tube out of the motor... A motor with a broken spindle nut will be loose inside the housing; usually, you can simply pull it out of the housing without unscrewing.  Replace the spindle nut, and all should be well again.

 

INSTALLATION INSTRUCTIONS FOR DEWERT SPINDLE NUT

Thank you for your purchase of the replacement spindle nut for your Dewert Megamat  motor.  This new spindle nut should make the motor work as it was when new, but it must be installed correctly in order to function properly.  We have found that following the steps below are the fastest and easiest way to accomplish this: 

  1. Remove the four screws holding the clevis mount to the bottom of the motor.
  2. Once the clevis mount is off, you will see a bearing in the housing; remove it and save it for reinstallation (notice before you remove the bearing where it is positioned in that motor housing; this is where the bearing should be for reinstallation later).
  3. Remove the cover over the armature of the motor; this cover snaps on with three plastic "catches" built into the cover.  The easiest way to remove this cover is to hold the motor assy. upright and strike down with the ball of your hand on the end of that cover; that should release the "catches" and the cover should come off.
  4. Look on the side of the motor assy. and find two either allen head or star shaped screws; remove those screws while holding up the armature of the motor (leave the Phillips screw in the middle with the red paint alone).  Once the screws are off, the armature can be removed from the spindle assy.  Once the armature is out of the way, you should be able to pull the complete spindle assy. out the back of the motor.
  5. Unscrew what is left of the old spindle nut off the worm screw, and screw the new spindle nut onto the worm screw, about halfway down.  Then reinstall the spindle assy. in the outer tube, aligning the three "tabs" on the spindle nut with the grooves in the outer tube.
  6. Push the spindle assy. in all the way, and then carefully move the armature back into place, aligning the end of the armature with the plastic spindle gear.  This is the only real part of this job that is tricky, as you don't want the armature and the spindle gear to bind up.  Reinstall the two screws through the side of the motor into the armature, and "snug them up" without overtightening.
  7. Install the bearing back in the housing, and try to fit the clevis mount back onto the motor housing.  IMPORTANT:  if the clevis mount does not fit snug to the motor housing, then something isn't aligned correctly - do not force the clevis mount on... Back off the two side screws holding the armature on, and reposition the armature on the spindle gear.  When everything is positioned correctly, the clevis mount will touch the motor housing on all sides.  Install the four screws in the clevis mount, and try running the motor without it being mounted in the chair to ensure everything is aligned properly.  If everything seems OK, then reinstall the motor in the chair, screw the stroke tube back onto the motor assy., and you are done.

 

If the spindle nut is OK, the problem may be a bent scissor mechanism or damaged framework under the chair.  Please do the following:

b)  Check for scissor or frame damage:

Turn the chair on its side,  Examine the entire base of the chair for bends or breaks.  Check the scissor mechanisms for excessive wear or broken welds.  Examine the wood and the lift frame near the scissors for scrapes or damage; The problem may lie with those instead of the scissors.  Check the base of the motor; there is a clevis mount (our part #8240) there that attaches the bottom of the motor to the chair frame.  They are made of a composite plastic , and it is a "weak point" of the motor assembly.  If you can't tell if the noise is coming from the chair frame or the motor, try removing the motor from the chair and manually move the chair to its various positions; sometimes you can find the squeak easier that way.  You can also run the motor while it is off the chair; if you hear loud noises from the motor that way, then the motor needs replacing.

Also check the end of the motor lift tube, where it bolts to the chair; the older Dewert motors had a plastic connector on the end of the push tube, and it was another "weak point" of the motor assembly.  If you find that broken, replace the stroke tube in your motor assembly with our new style stroke tube (our part #8244), and you are back in business.

4)  The chair is suddenly running very slowly, and sometimes won't work at all is someone is stilling in the chair.

It could be that the transformer is not working correctly with the household current, and it is now trying to work off the emergency battery backup.  In certain conditions, the transformer won't run on standard 120 volt power, but will still run off the batteries. To test this, do the following:

  1. Replace the two 9 volt batteries in the transformer with new batteries.

  2. Try running the chair without anyone sitting in the chair; see if the chair is running up and down, even if it still runs slower than normal.

  3. Now, with the chair still plugged into the wall receptacle, unplug the two 9 volt batteries

  4. Try running the chair again; if it doesn't run this time, then the transformer is defective and must be replaced.

 

5)  The battery backup system is not working.

PROBLEM: The batteries may be dead, or the battery leads may be damaged.

SOLUTION: Batteries need to be changed every 6 months (a good idea is to do this when you change your smoke detector batteries), or after every time they are activated due to power failure (the batteries only have enough power to run the chair for a cycle or two, then they will be dead).  If, after you change the batteries, the backup system still doesn't work, examine the battery leads for breaks, cracks, etc.  You can try replacing  the battery connectors If you have the room; if not, replace the transformer, if the battery backup is important to you (probably 90% of chairs with this feature don't have any batteries installed, or the batteries are dead, but manufacturers know that it is a good selling point, so they still use them).

 

Contact Information

Telephone            
Toll Free 888-871-0312 or 662-328-1493
FAX
Toll Free 888-871-2125 or 662-328-1480
Postal address
Medical Center Supply
1835 Highway 45 North  Ste 225
Columbus, MS 39705
Electronic mail
General Information: info@medicalcentersupply.com
Sales: sales@medicalcentersupply.com
Customer Support: custservice@medicalcentersupply.com
 
Send mail to webmaster@medicalcentersupply.com with questions or comments about this web site.