Atari Superman I/o problem

[T***@aol.com]

I have a strange problem with a Atari Superman pin that I am working on for someone. B2 MC14514B on the I/o was burned up and Q71 that feeds Q100. So I replaced B2 and Q71 the put the board back and they both burn up again. I tested Q100 and that looks good. The odd thing is on Superman Q100 doesnt feed anything. There is no wire on J19 pin 9. So I pulled q71 just to make sure and then a bunch of the other predrive transistors burned up along with B2. Anyone have any ideas

[John Robertson]

Post by T***@aol.com
I have a strange problem with a Atari Superman pin that I am working on for someone. B2 MC14514B on the I/o was burned up and Q71 that feeds Q100. So I replaced B2 and Q71 the put the board back and they both burn up again. I tested Q100 and that looks good. The odd thing is on Superman Q100 doesnt feed anything. There is no wire on J19 pin 9. So I pulled q71 just to make sure and then a bunch of the other predrive transistors burned up along with B2. Anyone have any ideas

Remove the Solenoid fuse before testing again. Check the outputs with a
voltmeter on B2. Are the voltages normal?

Unplug all the solenoid connector and replace the Solenoid fuse. Any
unusual voltages on any driver transistors when turned back on?

John :-#)#