Liftmaster 3800 won't stay closed?

[achilles99]

Hi everyone,

Lots of great info on the site about this unit, so hopefully a few of you pros have come across this issue. In the past several months, my 3800 is acting strange. I'll go to close the door, and once it reaches the bottom the motor feels like it isn't stopping, and then eventually the door opens back up.

I've set the limit and force settings, which fixes the problem for a day or two. Then the problem comes back. I've tried removing the cable sensor with the resistor trick, but that doesn't help either. The collars are tight on the unit, so I don't believe the pole is slipping or losing it's point of reference on the machine.

Any ideas?

[95vette]

Hello, Mine did that when it was new, called customer service and they sent me a new rpm switch, worked great after installing the switch. Phone number is 1-800-528-2817 6am to 7pm central time. Also make sure nothing is in front of eyes close to floor. Jim

[achilles99]

Thanks for the response. Nothing is in front of the eyes, since it works perfectly once I reset the limits and force of the machine.

Where is the Rpm sensor and how hard is it to replace? Hopefully, I don't have to release the spring pressure on the door and remove the entire 3800 unit?. It took me forever to perfectly balance it. It's still in balance now, I checked by using the pull release cord.

[95vette]

Hello, It's been a while since I did mine, can't remember exactly how it was done, but it was just a small switch inside box didn't take anything down, replaced it in place I believe. I'm at work so I can't go look for old switch. Jim

[achilles99]

Tech support agreed with you Jim. They called it a travel module part 41A5624-8. Thanks for the help!

I had written an email earlier to Chamberlain, and they gave me a quick way to get to tech support:

Technical Support Center Hotline at (800) 528-9131 this is a quick way to a technician: when the recording starts, press option 1. When the recording starts again, press option 6, M-F, 5:00 A.M. - 6:00 P.M., Mountain Time If you find that these solutions do not resolve your problem, please visit our Support Center for further information at http://help.chamberlain.com/.

[JB330ci]

Hi achilles99,

I got the same problem with my Chamberlain garage door opener. I called their toll free number and after several step-by-step testing trying to reset my down limit it just won't do it. So the tech support suggested the "travel module" (part# 41A5624-8) is bad. I ordered it on the phone right away but it's backlogged. Total cost with tax +SH is like $19.12. It will take about 2 weeks to get it. Have you got your replaced yet? just wondering.

[JB330ci]

Go to

http://chamberlain.custhelp.com/app/...-travel-module

you could download the instructions for replacing the travel module. Looks like pretty straight forward.

[pattenp]

Originally Posted by JB330ci

Go to

http://chamberlain.custhelp.com/app/...-travel-module

you could download the instructions for replacing the travel module. Looks like pretty straight forward.

Ok what am I missing. This link is not for a Liftmaster 3800 and plus I don't think that there is a part called a travel module in the 3800. There is a part call an absolute encoder that tracks placement in the 3800.

[achilles99]

Part is backordered, I won't be getting it for another week or so they said. Mine is under warranty, so I didnt have to pay anything.

They said the part is for a 3800, and goes on top of the motor. Supposedly, an easy fix. I'll report back once I install it!

[pattenp]

This is what is shown for the Liftmaster 3800. http://www.chamberlain.com/doityours...s/114A3472.pdf

[achilles99]

Patten, that looks like exactly what they described over the phone. Thanks for the instructions! Hopefully, that's what part they'll send...

[JB330ci]

Now I am really confused. The part number of the absolute encoder system on Liftmater 3800 is 41A6408. The travel module is for Chamberlain Whisper Drive Model 248754 and the part number is 41A5624-8 which is backordered. Looking at the instructions they are completely different parts. Don't know which one is which now. I hope they send me the right one.

There is another absolute Encoder System with part # 41A6118, see the link below

http://chamberlain.custhelp.com/app/...tail/a_id/1817

[achilles99]

Ok, Warren at Chamberlain has cleared this up.

3800PLD 41a6408 absolute encoder
3800 41a6118 absolute encoder

Travel module is only for whisper drive system 41a5624-8 (all dc motors)

If you have any issues, please call Warren. He is overnighting me both 3800 parts. I'm pretty sure I have the pld but I wasn't sure. If anyone needs the regular 3800 part (not pld), first post to this message gets it.

Btw, neither 3800 part is out of stock. Only the whisper light (which btw is the 3850, which is why some techs get it confused).

[pattenp]

JB330ci, I think the #41A6118 is the correct part # for the current residential Liftmaster 3800. That number is shown on the installation instructions. The # 41A6408 must be for a older model of the 3800.

Ha Ha... the # 41A6408 is for the Liftmaster 3900, which is the lite weight commercial version of the 3800.

[pattenp]

Looks like the 3800PLD and the 3900 are one and the same opener,

[justsam]

I think there is some repackaging, or "decontenting" as the auto industry calls it.

It looks like the 3900 now makes the power door lock an option, and it has a single button wall mount buttton, as opposed to the motion sensing, time of day, and temperature display on the "deluxe" wall button, included with the 3800.

Allows them to have multi tier price and "upsale" option.

[JB330ci]

So achilles99, did you get your opener fixed? Just wondering.

[JB330ci]

So after 2 weeks the "travel module" part for my opener is still back ordered at Chamberlain. I went to the local garage door repair dealer and found they carried it. Got one and replaced the bad one. Everything is back to normal now...

[achilles99]

Originally Posted by JB330ci

So achilles99, did you get your opener fixed? Just wondering.

Not sure why I didn't get an email with your question on this post, but yes... the problem was fixed BRIEFLY.

Then, it came back (albeit every few weeks instead of days). I think I just found the culprit... the collar is BARELY loose (I marked it). It was fine on the garage torsion bar side, but on the motor side it was SLOWLY sliding. I undid the collar screws, and low and behold one of them was actually broken in half. WTF.

Time to call Chamberlain tomorrrow!