I'd be interested in a transformer, a bad board etc. After troubleshooting my S1 i find the transformer is flakey. I lost half the balanced output and can get it back by messing with the transformer mechanically, rapping it etc.
Jim
Jim
Agree. It is extremely unlikely that there is an issue with the transformer. Look at wiring, relays, that sort of thing.
Audio1man is the goto guy.
Jan
Audio1man is the goto guy.
Jan
I would agree, I've only seen a transformer go once in all my years. But I've traced the signal to the input side of the Traffo and both sides are there on the output one side is dead unless I press down or up on the transformer or tighten the end bell, then it comes back. I had a short on the -22V line due to a smoked tantalum. This took out one of the driver transistors to the A side of the amp going to the transformer. I'm thinking one of the windings is bad and the slightest touch on it causes it to go open. Board traces have been resoldered and inspected, look ok.
I'll try to contact Duke also.
I'll try to contact Duke also.
You could just measure the DC resistance of the windings.
Directly on the winding connection on the xfrmr, not on the PCB or somewhere else.
Jan
Directly on the winding connection on the xfrmr, not on the PCB or somewhere else.
Jan
Thanks Jan. I did that, albeit at the board connections and it it intermittent on the one side of the output winding depending on how I touch wiggle it. I didn't want to believe it either. Next step it to remove the transformer and test out side of the unit.
Hi Jan
The 22 volt ps does not have enough current to open the TX. I talked to Jim and he is working on the solution. The 2 types of problems are that the TX pads are large dia and the trace has no teardrop and opens, or the TX pins have not been well fluxed and poor solder joint is now bad.
Duke
The 22 volt ps does not have enough current to open the TX. I talked to Jim and he is working on the solution. The 2 types of problems are that the TX pads are large dia and the trace has no teardrop and opens, or the TX pins have not been well fluxed and poor solder joint is now bad.
Duke
Well happy to report it's fixed. Duke really nailed it on this one. I pulled the TX off the board and the windings were all fine and identical. No amount of fiddling with it caused an open reading. Looking at the pads they seemed a bit dull and rough after desoldering nothing shiny. Like it removed every bit of solder because it wasn't stuck very well? No other way to describe it. I check the traces from the pads under a scope and they looked fine. I reinstalled it fluxing the crap out of it. Back in machine and working fine. So the solder joints were the issue.
Duke, I owe you one big time. Thanks a bunch!
Jim
Duke, I owe you one big time. Thanks a bunch!
Jim