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1PW[_3_]

wrote:

Snip, snip...

The unit was a 1992 Craftsman brand opener. There are no dip switches.
The transmitters are "learned" into the receiver. There were two
remotes with this system. The photo cells were working, btw. One
remote she keeps in a drawer so it is rarely used. I made sure the
batteries were good and tried each transmitter. Neither remote
activated the onboard led on the receiver board. I then tried erasing
the codes and then reprogramming the receiver. It still wouldn't work.
With two transmitters doing this the problem is probably the receiver
however you can't really tell if the transmitters are putting out can
you? So how would you determine if both transmitters are good or if
the receiver were good? Without being able to duplicate the modulation
scheme, the best I could do if I could determine the operating
frequency would be to hit this thing with a burst of CW from a signal
generator. I know that this would not operate the door but would it
disturb the onboard led thereby indicating the presence of RF being
received? How about if I take the transmitters and put them in close
proximity to my counter and if the transmission duration is long
enough I should be able to read the carrier? Lenny.

The OEM /might/ be Chamberlain LiftMaster. The Receiver board /may/
operate at 315MHz. Replacement receiver boards may run about $90USD.
A whole new DIY install is under $200USD. If you can get an exact
Sears Craftsman model/part number from the opener's label, more
detailed information could be forthcoming. Belt, chain, screw or
direct drive?

HTH

Pete
--
1PW @?6A62?FEH9

E=6o2@=]4@ [r4o7t]