Works when transistor grounded. Makes sounds when hit, but won’t engage. Ideas?
When you ground the tab, you are only proving the path from the transistor legs to the coil is good and coil works.
Doesn't mean the transistor is good or something back upstream from it isn't doing it's job. Or signal from MPU to driver board type stuff.
LTG : )
That would only leave a problem at the board....
Either the CA3081 (U19) or the decoder is broken.
its a 74154 chip on the MPU board. The PIA sends four bits in which decodes out to 16 possible combinations of outputs. Put the game in solenoid test and check activity at the 74154 chip with a logic probe or even a DMM on volts DC should be good enough as the transistions/pulse are slow enough. If the decoder output is good about all that is left is the CA3081 transistor array.
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