Also check the "SOl/SND BANK SELECT" signal that goes from MPU J4 to Driver J4. This signal should be LOW when solenoids are playing and high when sounds are playing.
(Topic ID: 262823)
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Silverball Mania
Bally, 1980
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Quoted from msarac:Slochar, that jumper is present and I have continuity across those pins. I also see the expected 5v at TP3.
Barakandl, that answer was WAY past my skill set! Put it this way, I did just dig out the logic probe I bought but never opened!
So it looks like the black clip to ground, the red on 5v? Which I can get from TP3 on the driver board correct? Set probe to TTL or CMOS? From there, which pin(s) am I probing on those J4s, and I'm guessing put the game into solenoid test mode while I'm doing this?
Appreciate the help guys!
Probe red on +5v. Probe black on Ground.
When in solenoid test check the LOW is lit at driver J4 Pin 7 / Driver U2 Pin 19.
When in sound test check the driver J4 Pin 7 / Driver U2 Pin 19 is HIGH with brief pulses.
You can also check the Driver U2 A B C D labeled pins change from HIGH / LOW on the probe during solenoid test. Each one should move to low at some point during solenoid test. If one is always high that will cause wrong/no solenoids.
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Seems like this problem comes up a lot and almost always related to connectors from MPU J4 to Driver J4.
Quoted from msarac:I still have 45v at all the coils, and they all work when their transistors are grounded so I think power is good.
Thanks for the details on the logic probe barakandl - all of those tests came back as expected. Driver J4-7 and U2-19 were low during solenoid test, high during sound test, and U2 20-23 all went HIGH to LOW during solenoid test.
I replaced the pins and headers on MPU-J4 and Driver-J4, and confirmed I didn't bridge any two pins that shouldn't be. Also had good continuity on the connectors between those two plugs. It still won't fire.
I noticed the driver board is not Bally but a Stern SDU-100 (10-24-78 Rev C). Assuming that's fine since those solenoids did work for a bit. I do have an Eight Ball Deluxe with the Bally AS-2518-22 driver board that works great - could I swap that into SBM to test? Figure if that works then the problem is somewhere on the driver board...
you can try the eight ball deluxe driver board. all the bally / stern games driver boards are interchangeable except for maybe some four flipper games need thicker tracks around the relay.
Next thing you can check with a probe is the driver board U2 74154 outputs. Put the game in solenoid test and watch a used output of the 74154 chip. Like U2 P9 for the right pop bumper. During solenoid test U2 P9 should sit high and briefly pulse low when the pop bumper should fire. You can check that output and a few others to determine if the decoded solenoid signal logic is working OK.
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