Help with intermittent STTNG fault

[johnh]

Hi all.
Hoping someone can help. Every now and then I get a fault with my STTNG where the Start, By In, Trigger, Plumb Bob, Slam tilt don't work. The slam tilt might be a red herring as I'm not sure this is working full stop, but the others intermittently stop working. I think it could be cold related as they seem to work when the machine is warmer. I don't think it's the column out as the other switches in the column are working fine, but could it be anything to do with the board that sits in the front of the cab under the left flipper switch?
Any suggestions gratefully received.

Cheers

John

 

[Moonraker]

Yes John either that board, bad connector at that end or cpu end or broken wire between the two.

 

[johnh]

Thanks (and hi ) . I guess I'd counted out a CPU issue as then the whole column would be out? What steps would you take to test which one it is?

 

[Moonraker]

Check which pins for the circuit, remove connectors on mpu and short to confirm fault not on mph, then replace connectors and repeat exercise on the coin door pcb. That should help narrow down the problem area then correct according to where the fault is.

Possible to cheat by swapping a coin door board with one from another game...

 

[johnh]

Thanks peter. So just short row to the column for the relevant switch on the main CPU, then also on the coin door board?

 

[Moonraker]

Yes and both sides of the coin door board...

 

[johnh]

Thx @Moonraker All sorted. Replaced the CPU connector from the coin door board.
Anyone casually browsing by, and interested in a really nice STTNG, it'll be up for sale shortly