Pioneer sx-550 "sizzles" on power on
Upon turning on, lamps flicker and you can hear noise on the speakers **even when just the ground wire of the speaker is connected - No positive wire connected**. This lasts a variable amount of time, usually roughly 5-10 0 seconds, sometimes longer. The audio then kicks in but more often then not, it is distorted. This again lasts for a variable amount if time (5-20 seconds), at which time the light stay on solid and the audio clears up. Once in a (rare) while it will turn on just fine, or the audio kicks in quicker and the flicker clears right up. However 90%+ of turns on result in this issue.
At first, I thought maybe the large filter caps, but I swapped a brand new pair in and no change. The I pulled the two 4 amp (power board) fuses, no change. Put those back, pulled the two 0.8a fuses which feed the preamp and such, no change. Put those back. Pulled the 1.5a lamp fues, well obviously the lamps stayed out , but otherwise no change. I don't see anything else on the schematic below.
I wonder if the actual AC switch itself could be the issue? Though no amount of wiggling etc resolves anything. I also spray in the area, though didn't see any clear ingress opening for the switch so that probably did nothing.
Which brings me to my second problem. Once it is all powered up and working fine, the right channel is out. The amp itself is working and there IS audio output at the headphones on that channel, which means it's present at the switch. But there is no output on the A or B right set (or a+b). That switch (which is coupled to the AC switch) was spray but no change. Seem strange/unlikely that both a&B sets on on side would be out but again, I'm not seeing anything on the schematic (below) that explains it other than multiple connection failures there, yet that seems so unlikely to all be on one side.
Thoughts? Recommended things to check?
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