Old garage door opener control problems


Old 12-23-15, 12:33 AM
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Old garage door opener control problems


So my old Liftmaster (aka Chamberlain) garage control panel stopped working, and two new replacements won't work either. I called Chamberlain's tech support and they were only able to help me do troubleshooting that I already know, based on the garage door user manuals and some research I did over the net.

I think my wires are good, but it's hard to believe that two new control panels are defective. Anyway, below are more details of what was already done to troubleshoot things:

- originally installed 398LM control panel (came brand new when I bought the house 5 years ago)
- 888LM control panel bought from a seller in amazon
- 888LM control panel sent by Chamberlain tech support

1. Original 398LM door control panel started working intermittently. It will only work for a few mins then it stops working. On and off, but a lot more off than on. It came to a point that it rarely comes on.

2. Took out original control panel, replaced it with new 888LM door panel bought from amazon. Still doesn't work.

3. Switched black and red wires. Still doesn't work.

4. The garage door opens/closes when the ends of the red and black wires make contact. This leads me to believe that the wires running behind the walls from the unit to the control panel are good.

5. Did a short test of the control panels. Both 398LM and 888LM failed the test.

6. Made contact the red and black wires during short test. It opened/closed doors successfully.

7. Called Chamberlain tech support. Told them the story. 888LM control panel bought from amazon was deemed defective so they sent me a replacement for it.

8. Got the 888LM control panel from Chamberlain. Installed it. The LED lights were expected to blink rapidly for up to 5 mins, indicating it is charging, but it didn't light up at all.

At this point I am stomped. Could I have gotten a second defective 888LM control panel unit? Could the issue be with the wires and not with the control panels, given that contact between the red/black wires opens and closes the door? Any advice would be very much appreciated.
Old 12-23-15, 03:26 AM
Doorman2722's Avatar
Join Date: Oct 2005
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put a new (temporary) wire on terminals red and white then hook up any button to red and white and see if it works. The push buttons are polarity sensitive and can only be hooked up on way. If not you probably have a faulty Circuit board......Also how old is the opener? The 888LM is not backwards compatible with the green smart buttons or dip switches (even older units)

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