Sony MHC-GNX800 turns itself off

[Multiplexer]

Hi.

Stereo won't start.
Power amp supply-rail fuses VAPORIZED - black with melted fuse wire all over the inside of the glass.(something went wrong there...)

Power amplifier module is an STK412-150

If you try to turn it on(with new fuses fitted), the new fuses DO NOT blow, but the whole amp shuts off the second you press the power-button - even the LCD backlight is off, and just the power button backlight works - alternating between green and red.(about 1-second duty-cycle red-green over and over till you pull out the power plug)

If I remove the PSU fuses to the power-amp, the system does start up fine, but naturally, without any sound.

I think the STK module is dead, but I would like another opinion.

Can't measure the PSU voltages to the power amp module on the DC side of the bridge, as I can't start the unit up to measure them, but there is juice on the AC secondary of the welding transformer that the unit uses!


There's not much in the way of electronics in the power amp module - a couple of bridges, the STK, some filter caps, couple of relays a handful of SMD and that's about it. I have removed both bridges and tested them - they are fine, so I am about to replace the STK amplifier module, but would like any other opinions...

Can anyone tell me what the red/green flashing light on the power-button means? Obviously it is trying to tell me there is some kind of fault, but perhaps the flash sequence is different for different things?

[Multiplexer]

It was the STK.

Made an executive decision based on my knowledge, and replaced the STK.
Amp works fine now.