Hi everybody! This weekend I brought home a very nice & clean Black Knight. It's in a very great shape and it is complete functioning except for the diagnostic switches in the coindoor. If pressed nothing happens (except for the "Highscore reset"), so I cannot modify the audits.
I've tried another coindoor in order to see if that was the problem, but the same situation. The boards are already refurbished, all except the driver board (I'll do it soon) so it means, new interboard connector, new sockets, capacitors, etc...
Any suggestion?
Thanks in advance guys!

Yes, correct

The connector is in the right place (the second from the upper left).. I'll check the continuity first when I come back to work
Thanks for the moment

Ok guys, I've checked and the continuity between switches and connector is ok. Is there a method to simulate directly on the cpu board the switches action? In order to exclude definitively cabling or poor connections due to connnectors..
So.. any other suggestions?

Thanks Cheddar for your reply. I'll try this to exlude cabling as I already said. One question... without 1J4 in positions, the pinball doesn't start so I think it needs a momentary jumper or something else. Could this be a problem?
After that, if the switches doesn't work, what can I check on the MPU board? (considerating that the pinball works correctly and the board at the bench is ok..)

Great Cheddar for the hints! I've tried your method and directly from the board (grounding 1J3 or 1J4) the test starts correctly! I've also solder the ground braid to the woofer.. I don't know why, but without the test won't start.
Finally, I've cross-checked the coindoor with another one and I found that the female connector inside the cabinet (for coindoor) doesn't work well. It depends on its position.. I've to change it!
Again thanks a lot to everyone, especially Cheddar to help me!
Now I have another little issue with the sound board.. the background sound doesn't start immediately but it tooks several seconds once the ball is launched.. if you have suggestions for me, I will be very grateful!
Thanks again
Ciao