I killed my gottlieb system 80 cpu board

jacklegjim

New member
Joined
Oct 9, 2009
Messages
17
Reaction score
0
Location
Tennessee
I was having trouble with a pop bumper on my touchdown sticking on. While troubleshooting
I was making the switch from underneath with a screwdriver (a very big mistake) and shorted the coil voltage to the switch.It died as soon as the short occurred.All I get from it now is the GI works and the score displays show all zeros. The credit display is blank and it does not respond to any buttons. I have had successful troubleshooting and circut board repairs in past.I just do not know where to start with this one. I tried to trace back it on the print and if it sent high voltage on the +5v circut It could be multiple problems.
Anyone have any advice on where to start? I ordered a logic probe as a start.
Thanks Jim
 
Check your slam switch on your coin door. Next check your 7406's on the board. Feel for very warm to the touch chips... There is hope... :D
 
All fuses are good and all voltages are good. Slam switch on coin door is ok.
The z14 7400 chip is hot soon after the power is turned on and this chip is in the switch matrix return circut from the pop bumpers.I have some ordered. It would be nice if the fix was just one chip replacement. I will update after I replace the chip.
Thanks for all the help.
Jim
 
All fuses are good and all voltages are good. Slam switch on coin door is ok.
The z14 7400 chip is hot soon after the power is turned on and this chip is in the switch matrix return circut from the pop bumpers.I have some ordered. It would be nice if the fix was just one chip replacement. I will update after I replace the chip.
Thanks for all the help.
Jim

Yeah... checking the fuses was worthwhile but I would have been very surprised if one was blown and that was your whole problem. The current it's going to take to fry the ICs in the switch matrix is FAR less than the rating of the solenoid fuse. If you blew the solenoid fuse by shorting that voltage into some logic you know you've REALLY destroyed something. Anyone who's blown up a few pinball machines could tell you that ;)

Chances are good you blew up the logic driving the switch matrix. If you're lucky it will be a single 74xx chip that's under $1.

It happens. I've done stuff like this before.
 
Update on repair

I had to replace Z11,Z12,Z13,Z14,Z15 on the control board and now I am back to where I started at with a bad bumper driver board. I learned a very good lesson from this and maybe if someone else does this my experience can help them.
Jim
 
Back
Top Bottom