Samurai Shodown 2 cart no sound

[lithy]

Got this cart. Plays fine on two different boards (MV-4 and MV-1A). But has no sound. No BGM, no SFX, nothing. Both boards play everything else just fine, no sound issues.

Opened it up, I don't see anything obviously wrong on the board itself. It is an original cart, matches MVS board scans. But I do see some obvious corrosion on the cart connector. Just a little on the PROG board, more significant corrosion on the CHA board.

Tested continuity on as many pins starting from the right side of the CHA board (when looking at the back) that I could trace. Can't get continuity on the 6th pin which (assuming I traced correctly) goes to the bottom left pin of the M1 (again when viewed from the back).

Have a few other projects from a pile of junk I picked up, figured I would start small. Assuming this is the problem, how can I look to fix it? I have beginner soldering stuff but willing to get better tools/materials.

PROG board front/back, a little corrosion on the pins, but seems alright.



CHA board front/back, more corrosion on the pins, especially the right side when viewed from the back.

 

[Neo Alec]

If you're sure you found a damaged trace, patch it with a small piece of wire running from the pin on the rom to the top of the cart edge connector.

 

[max 330 megafartz]

Yep, run a bodge wire and see what you get.

 

[Heinz]

Soap up the pcb's and then blast it with the garden hose and dry it in the sun mate, she'll be right.

 

[lithy]

Soap up the pcb's and then blast it with the garden hose and dry it in the sun mate, she'll be right.

What's the sun?

Well, the two worst edge pins that had continuity issues basically flaked right up in little pieces.

I removed them and used copper tape to create a couple new ones then soldered some wires to the right spots on the M1. Seated the boards sans case into the cab and still no sound. Still looks and plays great, just no sound.

M1 rom is only responsible for sound right? Maybe the rom is bad.

I'm going to attempt to reverify all the M1 pins, but my two repaired ones have good continuity.

I know it's ugly, but I swear it's getting great continuity. No issues in any spot on the copper tape.

 

[channelmaniac]

The M1 ROM is the Sound Program ROM. Without it you have no sound. You have corroded connectors/traces on that edge connector that lead to the M1 ROM.

You can try to do things like scrape the corrosion or hit it with a fiberglass pencil and patch the dead traces or you can try to do something like peel off the bad connector trace and use some copper trace tape and 2-part high heat epoxy to lay down new edge connector contacts that you'll need to solder into the circuit.

Cart's probably not worth doing all that work to.