Yamaha M-70 Tripping Circuit Breaker

Been awful busy with work and other hobbies, mostly lurking here a bit now and then when I can find the time. Haven't touched any stereo gear for months and months short of listening.

The only time I had an issue with an M-70 popping the breaker as I recall was when one side of the amp was toasted (shorted outputs) and just pulling too much current. Looks like it was gone over but have you checked all the adjustments again? The X-power supply on them really is a bitch on the supply circuit for some reason.

I did align the power supply per the service manual.
 
I did align the power supply per the service manual.

I checked it and it was fine, no problems there, I even checked the photo coupler, idle current and DC offset too which was very close and only needed minor adjustment.

I am running an extension chord from the nearby bathroom for testing.

It just doesn't like the Arc Fault breakers, even 20amp ones, it's funny I saw one on Ebay for parts and the seller said it was working when he put it in storage years ago. But when he got it out to test it it blew a fuse immediately. There must be a fix but working out what and how.

I mean we run the vacuum cleaner, all my other gear, just something in the X power supply.
 
just something in the X power supply.
Its a phase angle control thing..:D Your breakers dont play well with the SCR firing transiate spikes.Then add a little "inrush" current.
 
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Turning on any one of my amps causes the lights to dim momentarily, and if I turn any two of them on at the same time, I'll pop a breaker :(

I try to wait at least 2 seconds between powering up each amp now.
 
Turning on any one of my amps causes the lights to dim momentarily, and if I turn any two of them on at the same time, I'll pop a breaker :(

I try to wait at least 2 seconds between powering up each amp now.

This trips any Arc Fault breaker with it the only thing connected. None of my other amps do it.
 
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