Dead Mac II

[Unknown_K]

Recently I snagged an original Mac II for the collection. 

I removed the soldered on batteries and installed a battery holder (stolen from my spare IIx) and replaced the old SMT capacitors.

Machine will not turn on with keyboard or back button, swapped a known good PS in same thing.

Jump started it with a battery and it does power on and the fan in the PS spins but no bong. Turns off with the back button but won't turn on again.

Any ideas?

 

[LaPorta]

Likely rotten traces from leaking capacitors. Especially in the right-rear of the MB near the RAM, there can be eaten traces from the old caps. I had to patch at least one to get mine to work. If you have photos of the board, that would help greatly.

 

[MJ313]

This may be helfpul for you 

https://www.downtowndougbrown.com/2015/03/explanation-of-the-macintosh-iiiix-power-onoff-circuit/

 

[Unknown_K]

Nice link MJ313

Under the System will not power on there are 2 links to this forum showing where the traces are. The second link is dead.

https://68kmla.org/forums/index.php?/topic/20403-mac-ii-powers-on-but-does-not-chime/?p=207088

Anybody have that picture?