Originally Posted by Rob Morse
Sorry, I was unaware, this can be the problem with this type of troubleshooting.
Assuming the driver was behaving itself when buttoned up, it is difficult to steer you in a particular direction, the failure mode is not a common occurrence. If I were to try and find the point of failure, and the symptom was the power cutting out, I would start with the controller and power supply boards before moving to the amplifier. I can provide schematics to aid in the diagnostic if you like.
I've replaced all the electrolytic capacitors on the sub's main PC board and the four sub-boards. Unfortunately, things are now worse. I only get random clicking, no incoming audio, and roughly every 25 seconds I get a "brrrow-rrow" sound like the sub's just been powered up. I swapped the caps back to the originals--same problem. So, something went south in the replacement process.
The provided schematics were hard to read but I was able to determine that all caps were installed correctly, and the values were in the correct places as I swapped them 1 for 1. What makes me worry a bit is that there are several trim pots on the sub-boards and no references on the schematics as to how to calibrate them. Consequently I haven't touched them.
Normally I order low-ESR caps when fixing power supplies for monitors. I ordered low-impedance caps for replacements for the sub, except for a few that were unavailable in low impedance models and used standard electrolytics instead.
Do any of these symptoms sound familiar?