Going to try this for 3rd time....It has been a few weeks since orig. post. I have had MSF for 4 years, all was working fine until a month or so ago.y MSF machine began acting up...Blowing different fuses at random. Checked the PPB and Power Supply Board in which most of the fuses have been blowing, but I think it might be an issue with the CPU since the PIA diagnostic light stays on.
Below is exactly what has been going on with the machine:
F2 and F5 fuses on PPB board, and f8 fuse blew just above the large blue capacitors on the backbox itself.
Replaced fuses, turned the machine on again and laser kick back coil was stuck on and fried. The tip36 transistor was bad at Q1 on the PPB, others seemed fine. Fuses F9, F6 on the same PPB was blown.
Fixed bad transistor and diode and replaced burnt coil. Also replaced the bad fuses again, and then f7 and f5 on the PPB board blew again and no display came up. One fuse F5 on the Power Supply Board was also blown.
replaced blown fuses for the 3rd time and now, All diag. leds on the CPU stay lit and no coils are activated. Also fuse f7 on PPB board blew as well as f5 fuse on power supply. Replaced all of the fuses again and now the F7 and F5 on the power supply board still gets fried upon start-up.
Took all boards off and bench tested the CPU board with old power supply the voltage at 5v, 12, and -12 were all in spec. and the PIA light does go off on the bench. If this is good on the bench, then are the chips on the CPU board fine?
tested power supply board on the bench and those voltages also in spec., though not under any load from PPB board or DMD. I also replaced the 32volt Bridge rectifier off board that resides in the backbox.
Now upon start up, I had nothing connected to the PPB, just the plugs to all the CPU board and Power Supply board and fuse f5 (4amp that controls 32v. coils) keeps blowing. And again, I have nothing from the PPB plugged in
so the CPU will not boot and all the (3) diagnostic lights are still on.
This is driving me nuts and I need someone who really knows Sega/Data East boards to help me out!
Any suggestions on getting this machine back to order would be most appreciated.
thanks
p