Chamberlain Lift-Master Remote Control Problem

I searched previous posts on this topic and did not find an answer, so if I missed it, I appologize.
We have a residential Chamberlain Lift-Master H.P. (Part No. 41A5021- E, Date: 04/00) garage door opener with a remote control problem; it continues to work fine with the regular 110V switch. (It worked fine with the remote up to the date it failed.)
I suspected the remote control needed a new battery, so I bought new batteries and replaced them in both remotes. That failed; I thought maybe the new batteries were bad, so I bought another set and again replaced the batteries; still no luck with either remote. What else can I check before calling for a service repair?
Thanks for any advice you can provide. Lee
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

120v doesnt control it on a wall switch, its probably 12v. Try to resync it, there is a button on the unit. mine has an antenna check yours to be sure it tight.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lee wrote:

Have you tried unplugging the power for a minute? Chamberlains sometimes have problems that are cleared up by doing that.
If re-synching the remotes to the overhead unit doesn't work, I'd suspect a broken antenna in that unit because the wire sometimes cracks, right at the circuit board, but it may look fine because the break is inside the wire insulation. Don't work on the opener except with the power turned off, both because of electric shock hazard and the possibility that the opener may unexpectedly turn on and yank your hair (some people have literally been scalped) or cut off a finger. Also use an insulated ladder, bench, or chair, not a metal one, because of the exposed high voltage.
Sometimes remotes go bad because the circuit board or a solder joint cracks from being flexed when the button is pressed, but it's unlikely both remotes would develop such a problem simultaneously.
If you contact Chamberlain, try to speak with a real technician, not an installer. The techs know a lot more, such as the problem old models had with the wall button that was solved by replacing it with a fancier lighted button (had to do with Chamberlain using the same wires for the button and the optical sensors and different voltage levels for each).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It is hard to believe both remotes failed at exactly the same time, so it is 99.9% likely the receiver has failed. The power off for 10 minutes, and then trying to resync sounds like what I would do. The receiver output puts a relay closure across the same pair of contacts that the wall activation switch shorts out, so if the wall switch still works, that leaves only the receiver. A cracked printed wiring path is likely, especially where the antenna is connected to the Printed Wiring Board (pwb). You could try resoldering the copper paths on the pwb, buts it sounds like you don't have much experience along those lines. Maybe you could get a skilled DIYer in your area to do the soldering for you for a beer or two.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.