5400/160 logic board looks ok but seems dead

[killvore]

Hi everybody! I have a 5400/160 that I pulled from a machine which I'd like to get up and running, but I'm stuck.
- The machine did not bong or output video when I fired it up
- I've also tested it in a known good 6200 (where it currently resides), still no bong or video. The speaker pops but I assume this is the PSU firing up.
- removing the ROM chip does not give a chimes of death
- I've recapped it and cleaned it. There was a little crust under 2-3 of the capacitors but there did not seem to be any damage.
- There was a little green corrosion around the battery, I am wondering if acid may have crept into the com slot
- I tried reflowing one of the edge connectors, boy that last row has something really sucking the heat out so had a lot of trouble (which is why they look a bit nasty, but I don't think anything is bridging)

I think my next step will be to desolder the com slot but that looks to be a huge PITA so very open to other ideas and suggestions!

(closeups in reply)

 

[killvore]

Some closeups from the front and back

 

[killvore]

and finally, detailed shot of the battery area

 

[Callan]

Heya Killvore!
I'd go back and check your cap work first. It looks like R33 might be shorting to a via, but I'd check them all up close and make sure your not shorting anything. The processor looks like legs might be possibly shorted on one side (bent), and there looks like a solder short on the opposite side. I'd also scape off the lifted/corroded mask in the battery area and check for any broken traces (by the B especially). Re-tin exposed copper. Also check for any left over solder causing shorted traces throught the board.. Bar that I'd confirm all your clocks and start at the cuda.

 

[killvore]

Nice! Thank you so much - looks like a busy monday for me Will definitely also check the caps, I am particularly embarassed about C115

 

[Callan]

It's all fun and games! It's what we do for fun, so never be embarassed. To quote old Frankie,"and I did it myyyyy way!"

 

[Callan]

Here's a visual of the possible shorts I saw on the processor. I'd look at all of the legs up close to verify there aren't any others just to be sure.

 

[killvore]

Oooh thank you - yes this definitely looks suspicious This is a big help!

 

[killvore]

Couldn't resist and had a quick poke at the CPU - cleared off the solder blobs and pushed the legs back (chisel tip ftw), the CPU and a couple of the other chips get hot when I power it up but still no other life signs unfortunately! Will investigate more on monday