Mac Color Classic unwilling to boot, how to bench test?

[ironborn65]

Hi pals,

I have a troubled Mac CC which refuses to boot.
The logic board has been recapped, caps where not leaking.
The analog board:
- has been recapped, at least the one recommended by Bruce
- I replaced a faulty TDA4605 (there was a short across pin 4 and 5)
- the two optocouplers have been tested OK
- an IRFBV40 was replaced because it was not identified as a MOSFET ( I have a tester of passive components)

This MAC has a soft-start, so I do not expect to find +5 and +12 in the external part of the connector (1) where the Molex will be derived.
I found a stable +5V in the 3rd pin of the long connector (2), for me it is the stand-by voltage, I was positive it was OK.
But when assembled, pushing the ON button in the keyboard does not start anything, dead-silent, no +5V in the HD Molex.

I have two questions for the community here:
- I would like to test the logic board independently of it's analog board, is there a way to inject the voltage? Is there a schema of the pinout of the log connector? I least I can remove one variable from the equation. Maybe it's the faulty ADB or the EGRET. A chime would be enough at this point to exclude the logic board.
- how can I trigger the ON of the analog board by mangling with the connector pins? I know how to do this on a IIsi PSU, but here I have no information.

And no, I do not have a spare Mac CC

tks

 

[bibilit]

The Egret is a main culprit here. Most of the ones i have been dealing with were in bad shape.
Most only required a removal, leg cleaning and that’s it.

 

[ironborn65]

thanks @bibilit , I have some hurdles in removing a SMD IC.
I would be keen to remove and clean the EGRET if I was sure the PSU works, and I do not know how to force the start-up.

I found here the partial pin-out of the weird connector https://powercc.org/takky/
I might try to short pin 23 with the 7, it it?

 

[8tto]

I haven’t tried it myself, but read several places that you can start the CC without the logicboard. At least you should get the fan and HD spinning and have some indication of a functional analogboard?