Got this CPS1 for repair and I have some questions

[pacoarcade]

Hello, I found this CPS1 board very cheap and I couldn't resist so I got it.

The board came with lots of flux in the CPS-A-01. It lacks some LSxxx chips and a capacitor and it has broken resistor arrays and two lifted pads. I don't think I'll be able to repair it, and possibly the problem is in the custom chip, but since it looks poorly reworked I plan to get the missing components and run it.

This board comes with Unicon and Tk capacitors. In my experience with Sega Mega Drive console, these capacitors almost always were way out of spec. Is it possible that they may affect other areas of the circuit and not just audio? for example not blocking DC or some other capacitor related problem. I'd like to know if it's safe for the circuit to run a CPS1 board with bad electrolytics.

Any idea on why the green wire patch is there?

Is it possible to run only the A board to get some useful information? what should I check to avoid damage if I connect a B+C board to test this board?

I attach photos of the board before and after cleaning. Any suggestion is welcome!

 

[tiff_lee]

I don't have a board in front of me to look but whats on the opposite side of the board where that jumper wire is? is there a parallel track that is damaged?

I can't make it on my laptop but are the lifted pads on the resistor arrays? jumper wire from base of resistor array to wherever the track goes, adjacent component/via etc

What were the problems with the board apart from what you have stated, i.e functionally did it not boot up, no video/audio etc

 

[xodaraP]

That looks to me like a board that's been well harvested for parts after they made an attempt to fix it

Broken resistor arrays, missing RAM and logic and a reworked A custom

Personally I would keep it as a parts donor and find another A board

 

[pacoarcade]

Hi, the board doesn't have missing RAM, it has narrow ram modules. The board has footprints for both wide and narrow (not sure if this is the correct term) RAM, you can observe it in the first photos.

I've not tried to boot the board yet, I plan to get the replacements for the missing parts first. Are there generic replacements for those resistor arrays? if so, any tip on how to look for them?

This board will probably end up as a source for specific parts for other CPS1 boards, but first I'd like to know if the CPS-A-01 chip is broken or not.

I found two lifted pads are in the LSXXX chips. I attach a photo of the opposite side of the jumper wire, I can't find any broken trace.