Hey everyone!

I have a 2 fold issue with my nba fastbreak I believe. I’ll do my best to explain:

If any bulbs are connected in row 7, and you test any bulb in column 1, the bulb you’re testing will light along with the bulb in that column but row 7 as well as the bulb that’s in the same row as what you’re testing but column 7. This will not happen if you test any of these other bulbs. Only when you test the lamps in column 1.

The behavior is the same if you test the next column. The same column row 7 will light and the same row column 7 will light.

Now. Issue two. If you test any bulb in column 6, the adjacent bulb in column 7 will light. If you test the bulbs in column 7, everything is fine.

If I remove all bulbs from row 7, all the lamps test fine until I get to column 6. This makes me think I have two issues.

I have attached a pic of the lamp matrix for reference. Thanks for the help!

07AC5B7E-8C33-40AC-85E0-19CBC0D6DC45 (resized).jpeg

No idea. Where are the diodes that are associate with this row? Is it one diode for the whole row?

Sweet thanks. I’ll read up.

Tested transistors Q93-Q100 and they all test good I think. All read between .5-.6 when in diode test mode and testing the outter legs of the transistor.

Q105 is testing bad. Going to replace that and see if it fixes anything.

Anything else I should test while the board is out of the game?

LED

Seems to be an issue above my pay grade. Sending out to Hibler for service next week. I’ll make sure and report back with what the issue was so others can reference later.

Found the issue! There’s a diode in the middle of a wire line under the playfield. It was shorted. We replaced and it’s all good!

It was the lamp wires for the #1 saucer lamp above the playfield. The diode is in the lamp wiring underneath the playfield.