This still sounds like a cracked trace to me. I can't remember if Manley boards have solder mask on them or not but in any case a lot of the cracked traces that I have found have been right at the transition point between the pad and the trace (which is also where you go from tin to solder mask, hence the question). If there's solder mask, I would scrape off about 1/8" or so where it meets the pad and then bridge with solder from the pad out along the bared trace. If there's no solder mask, I would clean the trace with some isopropyl and then do the solder bridge as mentioned above. OR, just try metering from somewhere on the trace to the pad, as per my earlier post.Manley has been wonderful. They've given me a lot of tips, sent me a new set of caps, and checked in to see how I'm doing. Way more than I would expect, and more trouble for them than simply tell me to just send it to them for repair.
I've finally found something repeatable:
After all that, it makes the noise when it is idling by itself. If I press down firmly on the transformer, the noise disappears. My hunch is that the issue is in the input transformer pcb itself, meaning it's not the pressure that creates on the main pcb that is restoring the proper connection. I've passed this on to Manley to see if it sounds familiar to them.
- If I press down firmly on the input transformer, the noise goes away, until I remove the pressure.
- pressing down with a pencil on the main pcb around the transformer does not have the same effect.
- I removed the transformer (tricky job), since there are some solder pads under it I could not reach to re-flow. I cleaned up the header, re-installed it, and installed a couple jumper wires to be sure I could get a good connection to those pins that I couldn't reach easily to solder well.
- I re-flowed the points on the input transformer pcb itself