Hi I'm new to these forums so hello to everyone.
I have a problem I was wondering if you might have any ideas as I'm not sure where to start, I have bought an old black knight 1980 Williams sys 7, I've been following all your suggestions in regards to general troubleshooting.
I originally received it with acid damage to the driver board and interconnectors
Seemed at first I had dead CPU with 0 on the led mpu, I ordered new flipper roms and CPU game roms and the pinball has come back to life.
Also I replaced the interconnectors, lamp resistors and cleaned up all the acid with vinegar solution.
But now I have new problem, mpu seems to pass Startup and goes into attract mode, the lights flash as normal on the play field but the ball return coil keeps popping off over and over, I've tried loading in all 3 balls but it keeps popping as if the ball return switch was stuck.
I check the switch and it's ok, even swapped it around with another from the play field but no luck.
So the logical course woud be to start looking at the driver board, but I have another fully functional system 7 here too (firepower II) so I pulled the driver board from that and stuck it on bk but same problem.
So I thought I'd test the mpu board, I pulled the roms out of firepower II and stuck them into the bk mpu using the firepower II driver board, then I stuck it into firepower II, goes into attract mode like bk but the ball popper is popping still and also a few other coils are popping here and there like the bell and others. If I flicked the power I could start a credit, but I couldn't trigger credits as normal while it was like this. I started a game but seemed like switches weren't working and not lighting targets.
So I stuck the new bk roms into the firepower II mpu and stuck it into bk but it fails startup with error 7 so I couldn't test the unit any further.
I've ordered Leon's test rom and am about to try probing the mpu, everything seems to point to a problem with the switch matrix, but everything also seems to point to the mpu being faulty somehow. To me it seems like it's pulsing power to the switch matrix and it's stuck somehow.
I can switch to diagnostic mode and the ball popper then stops and I can run thought the diag switches as normal, all coils seems to test normal on both machines.
Ok I'm sorry that was a long read if you have any thoughts I would appreciate it.
Thx
