Overhead Door Opener Controller Question

[phurm]

A neighbor gave me a Model 551 Overhead Door Corp. garage door opener which I have stripped down to the controller board. I want to get this working so I can use the remote control. I would have assumed that I should be able to get a control signal out that might be just a quick pulse but can't find one.<p>This board has 3 relays on it. Only one seems to activate. It will open and close about ten times at about a half second interval then stop. Neither of the other 2 do anything.<p>I expect that in snipping extra wires that were "unused" when I disconnected the motor that I might have interrupted a return line of some kind.<p>Anyone know anything about this model? Should I truly expect these other 2 relays to work or are they perhaps part of a safety circuit? Is there any way to get a short contact closure out of this board?<p>Essentially, I want to replace my old controller with this newer one. I can easily tap into the wire to the push button on the wall so a short relay closure "pulse" would be ideal.<p>I can always add circuitry to do this but I was wondering if I could just replace a wire that I ripped out to get one of the other on board relays to do this if it was ever supposed to.<p>Any thoughts appreciated.<p>TIA<p>Paul Hurm
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[Donald S. Lambert]

Idon't know the electronics but I do know there is a way for the door opener to detect if there is a child in the path of the door. And that might be the wires you cut. Also there is a way to detect if the door hits something so again might be a wire you cut. Really this is guess and by gosh on my part since I don't know the electronics involved but I did have to figure out how to set the door so it would stay closed and actually close all the way. Greybie

[Will]

I can't figure what a third relay would be doing. It needs two relays to run the garage door, one to open it and one to close it. If you have the child detection device (Which I think all modern devices are probably fitted with - mine isn't) then that is achieved by a photo-electric transmitter and receiver installed in the plane of the door about six inches or so above the floor. The device which detects whether or not the door has fouled some thing solid before it is completely closed - is a spring mounted loose pulley around which the drive chain or wire passes. If the door strikes an object which stops it then the increase tension in the drive moves the loose pulley which operates a micro-switch and reverses the movement of the door. Hope that helps a little !

[Calcbert]

When I took apart an old Sears opener, there was an opto-interruptor set up for the motor shaft. (Opto-interruptor = LED shining on phototransistor, with something blocking it once in a while.) I suspect this was expected to be interrupted at a known rate to indicate that the motor had not stalled. Perhaps the opto-interruptor for yours (I bet it has one).<p>Your best bet is to keep the motor on the opener and run it (without chain drive stuff). Use an oscilloscope to see how often the opto-interruptor is tripped. <p>Since emulating the turning shaft would be annoying, it might be better to reverse engineer the circuit a little more.<p>I suspect one of the relays is for a light included with the opener. These often stay on for 5 minutes after the motor activiates, so it'd be impractical to run it off of the motor relay.<p>Hope some of these ideas help.