Are you a System 6 wizard? then here's a good one for you

Blackout driver board, recently serviced by pinball_services (eBay), has been working normally for a few days then both flippers stopped working...

I swapped it out with another driver board (from my working Firepower) and Blackout was back in business. Then I tried the bad driver board in my Firepower and got the same symptoms: everything works but the flippers. This driver board is the obvious culprit.

So I replaced R25, R26, R27, diode D1, Q13 transistor, flippers relay, and even the 7402N close by... But flippers are still dead.

What can I do? anything that I missed and that I should check? any test that could point me in the right direction? I would prefer to not return that board again for service (already spent a lot on it), I have some decent soldering/desoldering equipment but no logic probe, I can only do basic voltmeter testing.

I'm a bit desperate so any help appreciated Thanks

Few pics for reference :

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Thanks for chiming in Chris

Lesson learned for the eBay repair "tech".

Damn you're right, Q13 2N4401 is backward ! I stupidly put it in the same way all other transistors are on the board, but no, it's the only one with the flat side facing down... Duh. Always check the assembly drawing. 2d lesson learned.

I replaced it with a new one, flat side facing down and... It works !

Behold Mr Chris Hibler, the one, and only
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