Originally Posted by monomer
I've thought about just shorting across the relay to have it ON all the time but so far I've not gotten around to finding my soldering iron and solder... it's really just not been a top priority for me. However I'm surprised no one else has already tried this and reported back.
Well, I'm certainly reviving this thread from the dead. I was just posting about this exact fix on another forum. I'm having the problem with the autosensing circuit my PS-12. And I tried the method that monomer posted about above. I bypassed the K1 relay (P/N: 943-1C-48D) and it didn't work. Somehow the signal still needs to travel through the autosensing circuit to be played. That's the short story. If you're interested in more details read below.
When I turn on the power of the amp, the red standby light comes on, but when I connect it to the receiver the light won't switch to green, instead I get a flickering greenish-red light and no output. Before it got to this state I was having problems where the sub would drop out, and with the dropouts the light would go from green to red. Just as a test, I ran a 3.5mm headphone to RCA cable from my cell phone and when I turn the volume up to near-max on my cell phone I can get the light to turn green and the sub operates normally. So I believe it's something to do with the input detection circuit and it's right on the verge of detection.
I downloaded the PS-12 service manual found the output relay, bypassed the relay, then figured it would play with perhaps some potential side effects. It didn't work, same issue as before, not working from the receiver but did work with the cellphone. As for the side effects, the only one I experienced was when turning off the amp I would get one small *thunk* in the powering off process. No real biggie, but definitely bypassed the soft turn-off.