bally solenoid driver board 2518-22

[PINARCADE64]

I have a defective bally solenoid board from harlem globe trotter . I swapped the board with another and the problem was solved so its definitely a board problem. I replaced the tip 102 and still wont activate coil . I grounded the transistor and it works the coil.I checked continuity on all sides of tip and all is good. Im getting weird readings on u4 but rca 406 does not exist anymore. Any suggestions on what part to use ? also u2 may need replacing so may need to know what part number for that one too.

[HPR Pinball]

Check for ca3081 instead

[PINARCADE64]

there are lots of different models of ca 3081. Does H 406 make any difference ?

[HPR Pinball]

I don"t think but i"m no expert, you can check specs datasheet

[semicolin]

H406 doesn't matter. PM me, I have a spare CA3081 you can have that should work. I have a U2- 74HCT154 as well.

That said, before I start giving away parts, it would probably be best if you isolated the fault as it seems that you haven't done that yet. 99% of the problems on these boards are poor contacts: cold solder joints, faulty header pins, etc. You should be isolating the fault before replacing parts willy nilly, especially with ICs like these that are no longer manufactured.

You need to get the schematic for your game and find the solenoid driver page. Check ipdb, for classic bally it will be there.

Fire up the solenoid test mode, get your logic probe or oscilloscope on the output pin of U2 on the line that isn't firing. Does the output change state when it's supposed to? If so, U2 isn't faulty. Start working your way from left to right to find what point on your board isn't behaving the way it is supposed to.

If what I'm saying makes no sense to you, post which SCR line you're trying to troubleshoot and I can help point you in the right direction.

[semicolin]

Here, I've attached the Solenoid Driver Board schematic for Harlem Globetrotters.