MagicianLord77
Enthusiast
Hi guys, I've got hold of a Sega Title Fight cabinet to be restored, probably haven't been turned on in many years. So as first step I took the huge metal cage from its inside, opened it and found a pristine System 32 Multi board, looks almost like straight out of factory.
As first step, connected it to my Aero City by one of its 2 jamma edges (left monitor), it works perfectly, awesome sound too!. Then tried the other connector (right monitor), it works too, but with a minor issue: vertical lines/stripes on almost all sprites.
Looking closer at this issue I notice that:
Logic Probe'd all 16 ZIP SRAMs from the frame memory sector of the affected side, all had signals except pins 5 (SI/O4) and 2 (I/O4) of two of them, are stuck high, but same thing happens at the same SRAMs from the side that works well so it might just be that they are unused.
I'm using the fantastic schematics from Nemesis1207, they are from Spiderman (System 32 "single"), but since this issue happens at only one half of the board, they are very useful. Also, because of that I assume the fault should be located at something that's double on the board, like the Video Mixer IC.
Self test function gave OK on all ICs it could test. Marked them all on this photo from the internet.
Please check attached pics and video displaying the issue: https://imgur.com/a/mPTA05A
Any tips how to continue troubleshooting appreciated
As first step, connected it to my Aero City by one of its 2 jamma edges (left monitor), it works perfectly, awesome sound too!. Then tried the other connector (right monitor), it works too, but with a minor issue: vertical lines/stripes on almost all sprites.
Looking closer at this issue I notice that:
- 1 of each 4 lines has the issue (1 bad, 3 good)
- Lines seem to be at sprites only, not background "tile" objects.
- If sprites move/scale/etc. lines don't follow them, seems issue appears at a later stage of composition because lines are always in the same place, anchored to the screen.
- Lines graphics seem to belong to the sprite, but wrong pallette. Some times pallete can seem negative (see fight presenter screenshot), sometimes it can almost match the color (see Pinky Norman character).
Logic Probe'd all 16 ZIP SRAMs from the frame memory sector of the affected side, all had signals except pins 5 (SI/O4) and 2 (I/O4) of two of them, are stuck high, but same thing happens at the same SRAMs from the side that works well so it might just be that they are unused.
I'm using the fantastic schematics from Nemesis1207, they are from Spiderman (System 32 "single"), but since this issue happens at only one half of the board, they are very useful. Also, because of that I assume the fault should be located at something that's double on the board, like the Video Mixer IC.
Self test function gave OK on all ICs it could test. Marked them all on this photo from the internet.
Please check attached pics and video displaying the issue: https://imgur.com/a/mPTA05A
Any tips how to continue troubleshooting appreciated
