Camtec Marriola MIG D1 does not power up

[reflexsa]

Hi all,

A friend gave me his car amp to try and repair. This is what it states on the aluminium housing:

Camtec Marriola MIG D1, 1 channel 3200watts max digital amplifier.
When power is applied nothing happens at all. There is no power light, overload light and as far as I can tell there is no rail voltages or any potential on the power supply capacitors.

I have opened it up and nothing looks obviously broken.
I can measure 12VDC on the center leg of the power supply FETs, I think that's the drain.
However when looking at the pulse with modulation IC, which is a TL494, I cannot measure 12V on pin 12 and there seems to be no voltage what so ever on any of the pins.
I measured continuity of the ground to the ground battery terminal and there is a connection there.

I am not sure where the 12V for the PWM IC is supplied from and I am struggling to follow the tracks etc without a schematic.

If anyone has any advice I would greatly appreciate it.

Thanks in advance.