Bally Solenoid Driver Board Diodes

JahBarron

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Almost all of the 19 diodes on the bottom of my 1978 bally Power Play pin's solenoid driver board test bad. The ones grouped with the 330 ohm resistors (all test fine) above the TIP102 and disk caps (both untested). Game plays as it should. Should I be concerned and change them before something bad happens?
 
Almost all of the 19 diodes on the bottom of my 1978 bally Power Play pin's solenoid driver board test bad. The ones grouped with the 330 ohm resistors (all test fine) above the TIP102 and disk caps (both untested). Game plays as it should. Should I be concerned and change them before something bad happens?

It does not sound like you are testing properly. What meter are you using to test them? How do they fail for you, shorted or open?

A decent amount of lower end meters will not have enough forward voltage needed to "turn on" the diode which in turn will provide false readings.
 
Thanks for your help.

I'm using a Fluke 117 all test within in range, however when I reverse the leads the show similar readings. If they were allowing voltage to pass through, it would be apparent in game play, correct?

I'm new to pin repair and I'm completely enjoying it... except when i put that electrolytic capacitor at C26 in backward. Thank god for fuses! It just took me a couple of days to figure out my mistake. Escaped unharmed, thankfully.
 
Thanks for your help.

I'm using a Fluke 117 all test within in range, however when I reverse the leads the show similar readings. If they were allowing voltage to pass through, it would be apparent in game play, correct?

I'm new to pin repair and I'm completely enjoying it... except when i put that electrolytic capacitor at C26 in backward. Thank god for fuses! It just took me a couple of days to figure out my mistake. Escaped unharmed, thankfully.

You are correct in saying that if they were bad gameplay would be affected.

It has been my experience with digital meters and the Bally solenoid board that for the most effective measurement, the diode must be taken out of the circuit.

Theoretically you should get a reading of about 0.6 volts across the diode with the leads positioned one way and a reading of open (OL on the fluke meter) with the leads switched.
 
What would happen as a result of me continuing to play the game with a bad diode?

I have the diodes to replace them, but I don't wanna go messing around if I don't have to. Electronics love to turn on me when i try and give them love/tune them up beyond necessary repairs.
 
What would happen as a result of me continuing to play the game with a bad diode?

I have the diodes to replace them, but I don't wanna go messing around if I don't have to. Electronics love to turn on me when i try and give them love/tune them up beyond necessary repairs.

If the diode was open then the related solenoid would not work. If the diode was shorted then the solenoid fuse should blow and/or the associated transistor would be fried
 
I'll just monitor the situation and leave things as they are for now. Thanks again for your help!
 
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