Channel 1 stuck turned off

[rjhodgefamily]

Well subject says it all. I can not seem to get channel 1 to turn on for the life of me. Not sure if I blew something on the board or what. Led always stays off even in test mode. Pretty sure when I built the board a couple weeks ago everything tested fine. Any ideas on what I should be looking for to fix the board? Is it just the opto chip or possibly something else?

Thanks
Richard

[tbone321]

You can swap the opto with one from a different channel but I would take a look at the PIC and make sure that it is properly seated in its socket.  I would also take a close look at your solder joints.  You may have a cold joint which could cause this.

[rjhodgefamily]

Ok this may sound like a silly question but is there an easy way to get at the back of the board in the CG1500 case? Or is it best to detach all the cords and unscrew the board and just remove it completely? I will double check the opto and pic when I get home this evening.

[tbone321]

As far as I know, there is no easy way to get at the back of the board while it is still in the case.  You can swap the opto and check the PIC while it is in place easily enough.  Another thing that you can do is slightly flex the board with a non conductive item such as a dowel or wooden spoon and see if the LED flickers which is a pretty solid indicator of a cold joint but that method doesn't always find it. If the opto swap doesn't fix the channel, you would need to remove it from its case anyway to repair it.

[taybrynn]

got a spare channel you can just swap ch1 to instead?

[rjhodgefamily]

Have a spare channel but hoping it is as easy as a bad/misseated opto or pic. Would hate to have to fix the programming on a dozen songs for one channel.

[rjhodgefamily]

So I am kinda sheepish about saying what the problem was. I somehow missed soldering one of the leads for the LED on channel 1. It must have been touching just enough for testing and then broke loose when installing.

Thanks for all the help guys.

[tbone321]

Yea, that happens when the board is lying on the bench.  Glad that it was an easy fix.

[UncleBuck]

For future problems you can work on the board without removing it from the enclosure. I simply unscrew the four screws and with the cords still attached gently pull the board over to take a look. I have replaced triacs that way without damaging anything else on the board.

[jnealand]

For future problems you can work on the board without removing it from the enclosure. I simply unscrew the four screws and with the cords still attached gently pull the board over to take a look. I have replaced triacs that way without damaging anything else on the board.

I have done this same thing several times.  I put some clamps on the sides of the case to keep the cords from trying to lay the board back down.