Fixed: 4 slot with corrupted graphics

Had a 4 slot in for repair for a board member that had corrupted graphics.

The Neo Geo logo screen had the words broken into jumbled blocks and there were "0" (zeros) down the left and right sides of the screen.

Checked the board for broken traces. Did not find any. Swapped the top board with my test board. Same problem - it's on the bottom board. Replaced the 2 74LS244 buffer chips that were driving the address lines for the graphics ROMs. No change.

This was still an address line problem since the problems were in blocks and not in vertical lines on the screen.

Took the logic probe and checked each address line at the top board. Noticed one of the lines only had a slow pulse on it instead of activity. Shorted it to the next address line over and the zeros went away and there was just garbled graphics. Traced that line back and found where there was a very small area of board between connector CN8 and the edge of the board that had taken a hit.

Patched the broken trace to fix the board.

Enjoy!

RJ

nice!

Amazing channelmaniac !!! You truly are the master.

Hey, I need to send you my four slot that has damage from a leaked battery. I can see two broken traces, but there might be more. Can you pm me an estimate of the repair cost?

Typically $30 as long as there aren't any connectors or Neo chipset chips to replace.

Tack on another 10 if you want a new battery soldered in on top of the repair.

Plus shipping.

RJ

my main concern is if it turns out to need chips or what not, is it going to get expensive real fast?

Can't tell you without digging into the board. Generally if the battery leaks it has to be removed, the gunk cleaned, and the traces patched. It all depends on the extent of the corrosion damage.