Exhumation of a VZ 2500 - is resurrection possible?

I just bought on ebay a VZ2500 in a pitiful state. The seller didn't protect the package, so the device broke in the corner.

After a big cleaning and replacement of the vinyl belt, I tried to make the monster work.

Quite complex result:
Externally, no LED lights up, whatever the mode, even the power LED is off.
The cassette player, turntable and tuner do not work. (You just hear a background noise.)
Surprisingly, only the AUX input works.

I'll keep looking, but if anyone has an idea, I'll be happy.

Daniel

If aux works that means the amp, preamp, power supply, pots, etc. all work.
Maybe check for loose wires/connectors?

Indeed, I have so far deduced the same things.
The most annoying with this machine is the assembly/disassembly time
There may be a problem on a broken ground solder.