|cwstrong Wrote:I've been fighting a sound issue with my Tron upright where Channels 4,5 and 6 have been unresponsive and just when I think I'm making progress...this week the screen went white and now flashes constantly with only artifacts present on the right-half the screen.
The yellow LED on the SSIO flashes once and then two or three times and then repeats. I'm looking at replacing the RAM at A6 on the SSIO, but could this be a ROM issue or something entirely different? I disconnected the purple 'reset' wire, but with no change. Any ideas???
Thanks in advance!
Again, WAY late and probably already fixed. But you'd be surprised how much stuff can be caused by that RAM on the SSIO board. Personally though, I think that if 3 channels aren't working... I'd put my money on the AY-3-8910 chips on the SSIO board. 1 controls channels 1,2,3 the other does 4,5,6... if you swap them and the other 3 channels stop working, while the 3 that weren't working do... then just replace that chip. As for a flashing screen with artifacts... I 've had that happen when I turn my machine off then on again really fast. It resets the hiscores and settings so I know it screws up the RAM chip on the CPU board (socket B2).
First thing I would do is check voltages... you want atleast +5 and +12... a little more never hurts. I run mine at @ 5.2V and 12.2V. If they're good, then check the "purple wire" (reset). Try taking it out of the picture... I HATE cutting wires so I would just pull it out of the connector going into the board set.
Also try reseating all the chips to make sure they've got a good connection. Make sure the legs on the chips are clean and make sure the sockets on the board don't have any broken solder joints on the backside of the board.
If all of that still doesn't do anything, find a friend with an EPROM programmer or get one yourself (never hurts... most of the time). Pull the program chips on the CPU board (D2-D7) and read them with the programmer then verify them with WinRomIdent to make sure there hasn't been any ROM rot or anything.