Post by John RobertsonPost by ***@gmail.comPost by PaulPost by ***@gmail.comPost by ***@gmail.comHi All,
I am working on a R&B with only the Svuk coil not firing. Starting with the coil. It is wired correctly and another coil was tested and did not fire. Good diode. 74volts at both lugs. The switch is read. Took a look at all the coils daisy chained properly. Moving back to PPB board. All fuses are good. Q3 is good, associated diodes and resistors are good. Driver board, Q 42 is good. Smaller 2n4401 transistor is good. Resistors good. 7408 reads good. Checked for cold solder joints. No loose or broken wires at the connectors.
Frankly, I am stumped. All coils fire except SVUK. Is there anything I am missing? Could it be a bad pin on the PIA.
Any help appreciated.
Thanks,
Craig
CARGPB23
More than likely a bad TIP36 on the PPB board. Is it actually Q3 that controls it? Lots of errors in DE manuals.
Jim
I checked all of the TIP 36c on PPB board. All checked good. They all read the same. Usually, a bad tip 36c gives either 0000 on the DMM or something like 0.100.
The one thing that I failed to do was to check the path back to the 7408 but the board had never been worked on so I am assuming that the path was good. Yeah, I didnt have a very good schematic and it looked like the customer had photocopied it from the internet. I asked him to order one from PBR.
But I have an email iinto to Stern since they dont answer the phone any longer. But have not heard back from them. I do not want to shotgun this, I would rather just find the problem. but thanks for your input.
What happens if you ground the tab of the transistor that controls it?
If it fires, you wiring is good, if it doesn't then something wrong w/
the wiring.
Paul
When I grounded the tab of the transistor nothing fires. There is also no voltage at the tab. The other VUK has 74Volts and the other tabs have 40V and fire when grounded.
I once had a problem like this on a Gilligans a long time ago. The TIP checked good but the kickback wouldnt fire. I finally decided to replace the TIP for the kickback and it fired. So, I am thinking I may just need to replace the TIP 36C and the 122, 2n4401. But if I do that and it still wont fire, Well then I just invested a little more time to it.
I am awaiting an email back from Stern on this.
If the coil doesn't fire when you ground the tab then the problem is
either at the coil or in the wiring between the coil and the driver
transistor - not the transistor or its support team!
Go back to the coil and check BOTH sides of the coil for solenoid power
(close coin door if needed). If you have power on both logs, then follow
the wire from the coil back to the connector at the driver board, use a
pin to gently probe the wire (minimum invasion to check the inner wire
for power) to see if the voltage is still present. I suspect either a
break in the wire or a bad connection at the driver connect plug for
that solenoid control wire...
John :-#)#
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Each lugs wires were fine. One goes to the connector on the driver board CN11 and the other went to the PPB board if my memory serves me right J8. The game is a customers of mine so i do not have access to it. But I did pull the connector and continuity check the wires. Now, without the connector connected, I did not get any voltage at the tab of Q42 but I did get 74volts at the tab of Q43. What I think I need to do is check for power at the PPB output. I should probably isolate the coil by removing the wires at the coil, then check again for continuity. That way i am looking at an incomplete circuit.Thanks for the help, much appreciated.