WH20 cpu controlled lamps

[pinballmania]

You can eliminate a large number of diode/ lamps by disconnecting all of the lamp circuit boards. If problem remains it’s due to one of the single sockets. If problem goes away reinstate the pcbs one at a time until you get the problem.

Looks like a short or wiring error. Examine each of the lamp sockets. Look for crushed tabs, reversed diodes, incorrectly wired socket. The banded end of the diode should have red wire attached. Non banded end no wire And other tab the yellow wire. Look for previous repairs as this is the most likely reason for a lamp wiring problem.

Unless reversed diodes rarely go short on the lamp matrix so looks for wiring errors first. Also check any loom connectors that lead to switches or lamps. If one has been mis plugged then you may have inadvertently inserted a short into the matrix.

 

[Spandangler]

Some great advice there guys. Thank you. I’ll try all of the above

 

[stoptap]

We will get this damn thing fixed if it kills us !

 

[Spandangler]

By crikey I think we’ve found it
I haven’t tried it yet as I’m off to work but it’s gotta be the culprit in the worlds most inaccessible place. Under the upper pf.



Thanks everyone. Beers are owed yet again

Edit. It worked. Whoop whoop. Case closed.

 

[stoptap]

Get in !

 

[cooldan]

If I was at home I’d insert a congratulatory but thoroughly inappropriate and nsfw gif at this point ..... like the one of two blokes ****ing a watermelon for example ..... so be grateful that I’m out and about and on my phone. Congrats dude. Diode wrong way way round I assume?

 

[Spandangler]

I’m very grateful if also perhaps a little disappointed!

Diode was incorrectly orientated and soldered to the wrong tabs. You can see in the pic that annoyingly the perp didn’t notice the remains of the old diode on the tab, thus causing me many hours of head scratching.