HHaase
Active member
This is getting annoying, and I'm slowly going through everything that I suspect, but I figured as I'm stuck at work and can't test anything right now, I'll throw a post up here.
I've got a Black Knight, which occasionally works at about 90%, with a couple non-important things not working at all such as a couple lights and the bell ringer.
But it's only working intermittantly. The rest of the time, solenoids #1 through #8 all lock-on once I try to play, which blows the fuse. I'm not even sure what I'm doing that makes it temporarily "work". Here's what I've done so far.
Replaced all the male pin headers on the driver board.
Replaced the interboard connector on the driver board.
Replaced all the wiring harness solenoid connectors.
Replaced both transistors for solenoid #6 (Had previously been replaced, solder jobs looked awful). Used a TIP102 instead of TIP120
Replaced the 7408 for solenoids 1-4 and the socket, same reason as the transistors. Used a 74F08 chip instead of the normal 7408.
Replaced a fried coil at #6, which had the sleeve melted in it.
Tested all coil ohms, all check good.
Tested all coil diodes, all checked good, but since you have to half remove them to test them I just replaced them all. (got a roll of 100 diodes for $4).
Tested all the TIP120/TIP102's as well as the 2N4401's on the board with my DMM, This is where it gets odd. With the wiring connector for the solenoids removed, they all test OK individually. When I put the connector back on, I get 5v at the base but 3.5v at the emitter on all 8 of these..... but normal on 9-16.
If I disconnnect the connector for these 8 coils, none of the others have any issues and work normally.... even if there are only a couple of them. Once I connect 1-8, these 8 all lock-on and the breaker pops. (using a 3amp breaker until I get this diagnosed properly.)
I'm at a loss here what to look for next. I'm going to try using the logic probe feature on my DMM tomorrow, but that's new to me and I'm not sure what I'm going to be finding. Anything else to suggest? I may also throw a new 74F08 for the 1-4 block of solenoids, that way all of these have new chips for them, and with a socket there I can also unplug them 4 at a time too. After that, then what? The PIA chip maybe?
-Hans
I've got a Black Knight, which occasionally works at about 90%, with a couple non-important things not working at all such as a couple lights and the bell ringer.
But it's only working intermittantly. The rest of the time, solenoids #1 through #8 all lock-on once I try to play, which blows the fuse. I'm not even sure what I'm doing that makes it temporarily "work". Here's what I've done so far.
Replaced all the male pin headers on the driver board.
Replaced the interboard connector on the driver board.
Replaced all the wiring harness solenoid connectors.
Replaced both transistors for solenoid #6 (Had previously been replaced, solder jobs looked awful). Used a TIP102 instead of TIP120
Replaced the 7408 for solenoids 1-4 and the socket, same reason as the transistors. Used a 74F08 chip instead of the normal 7408.
Replaced a fried coil at #6, which had the sleeve melted in it.
Tested all coil ohms, all check good.
Tested all coil diodes, all checked good, but since you have to half remove them to test them I just replaced them all. (got a roll of 100 diodes for $4).
Tested all the TIP120/TIP102's as well as the 2N4401's on the board with my DMM, This is where it gets odd. With the wiring connector for the solenoids removed, they all test OK individually. When I put the connector back on, I get 5v at the base but 3.5v at the emitter on all 8 of these..... but normal on 9-16.
If I disconnnect the connector for these 8 coils, none of the others have any issues and work normally.... even if there are only a couple of them. Once I connect 1-8, these 8 all lock-on and the breaker pops. (using a 3amp breaker until I get this diagnosed properly.)
I'm at a loss here what to look for next. I'm going to try using the logic probe feature on my DMM tomorrow, but that's new to me and I'm not sure what I'm going to be finding. Anything else to suggest? I may also throw a new 74F08 for the 1-4 block of solenoids, that way all of these have new chips for them, and with a socket there I can also unplug them 4 at a time too. After that, then what? The PIA chip maybe?
-Hans