Skateball MPU resistor (TECH)

tomdotcom said:
Ok I traced all the wires by hand and using the schematics. All the
wires line up for connector J3 on the transformer board going to the
all the other boards. Except for one exception.

I have the transformer wire from a2j3-13 going to Solenoid Driver
board a3j3-5. The plug connector schematic says its supposed to go
from a2j3-13 to SOL. BUSS

I have no wire at a2j3-9. The plug connector schematic says its
supposed to go to a3j3-5, a8j1-9.

Thoughts? Would this cause my issue possibly?
Click to expand...

Nope, not it ... but keep tracing.
A2J3-9 and A2J3-13 are the exact same signal on the rectifier board -- both are 43V out from the rectifier board. One goes to solenoid bus, other goes to relay (A3J3-5). If the two wires are reversed, it won't matter as they both come from the same place. However, for sake of tracing the machine at some later date - best to put the wires where the manual says they should be.

To me - it still sounds like a short between A3J3-5 and A3J3-6... somewhere. Not necessarily a short at the connector but somewhere in the wiring.

Ed
 
Just to clarify, I have no wire at a2j3-9. Isn't there supposed to be one there? (One of the wires is yellow, which I have) the other one is supposed to be white/yellow. That wire is completely missing altogether :?

Don't I need a wire going to Sol Buss? As per the manual?

Just want to make sure..
 
I did take alot of pictures. Not sure that would help. Too bad I didn't live up in Fort McMurray still it'd be alot easier to come see Lindsey. Wish I had someone like him that close to tutor me. Your lucky to have a friend like that.

I'm getting closer slowly. At least I've ruled out some things already.
I unplugged j1 and j3 and tested j3 pin 12 on the rectifier board and got 44.4. So at least that much is right haha.
 
I'm a little confused with what you've actually tested at this point so let's just go through it one step at a time. The first thing I would do is remove the transformer/rectifier board assembly from the machine and test it. Clay describes a good procedure in his guide:

http://www.pinrepair.com/bally/index1.htm#ps

Testing Rectifier Board Upgrade Work.
After doing all the previous rectifier board modifications, test your work right on the bench, without installing the power supply back into the game. To do this requires only a power cord, and two alligator clip wires.

Connect the two alligator clip wires to connector J2, pins 6 and 7 on the rectifier board. Then connect the other end of each aligator clip to a 110 volt power cord. When plugging the line cord into the wall, the power supply will be turned on. Then test the rectifier board's "test points" for proper voltages. The voltages may be slightly different than previously dicussed above, since there is no load on the power supply. No load can cause voltages to vary somewhat. Connect the black (negative) lead of a DMM multi-meter to R1 or R2's lead closest to the fuses. This is approximately the readings that should be seen:

* Gnd (AS2518-18/-49): R1 or R2's lead closest to the fuses.
* Gnd (AS2518-54): R1 lead on the right.
* TP1 (AS2518-18): 6.4 volts DC.
* TP1 (AS2518-49): 8.2 volts DC.
* TP2 = 195 volts DC (could be as low as 150 volts).
* TP3 = 13.5 volts DC.
* TP4 = 7.5 volts AC.
* TP5 = 47 volts DC.

If the voltages seen are drastically different than the above, check your work. Also check resistors R1 (600 ohms) and R2 (25 ohms).

Test your work with the power supply installed in the game. Just hook up connector J2 (only!), and leave J1 (playfield power) and J3 (logic board power) disconnected. Turn the game on and check the voltages as described above. Having the J1 and J3 connectors removed will isolate the power supply from the rest of the game.
Click to expand...

Once everything is working on the bench you can install it in the machine, connect only J2 and test the voltages again.

Once that is done you can start connecting up the other boards and testing them one at a time starting with the regulator/driver board, then the MPU, and then the lamp driver. From there you can worry about sound and displays.

That's what I would do...

EDIT: Be careful connecting AC straight from the wall to the rectifier board. You need a fuse in line with that AC. There will be no load on the board (other than the bridges) so if everything is connected properly you should be able to use a pretty low amperage fuse (maybe 1 amp). If you've connected something wrong and you apply AC from the wall with only the breaker at the panel protecting it you could have a big mess on your hands.
 
Last edited:
I have tested all 5 test points on the rectifier board already. Everything was within spec. So that should be good. I also traced ALL the wires going out from J3 on the rectifier board and they all went to the proper spots on the SDB and MPU, etc.

I'm going to wait until I get the known working solenoid board from bstnguy. Then I'll install it and unplug the other boards.

How should I test the SDB & MPU?

What should I have plugged in? What shouldn't be plugged in?

At what points do I test on each board? (SDB,MPU)

In dummy terms of course :) hahha
 
This would be a start I imagine?

Remove Connectors J1,J2,J5 and HV Fuse from the Solenoid Driver Board.
and Remove Connector J4 on the MPU Board.
After doing the above and checking the power supply rectifier board voltages, reconnect the rectifier board's J1 and J3 connectors. But remove the MPU board's J4 connector and the Solenoid Driver board's J1,J2,J5 and HV fuse. The MPU connector supplies power from the power supply to the MPU board. The solenoid driver connectors are the .156" molex connectors which provide a return path to the solenoid driver board. Removing the HV fuse doesn't allow the score displays to burn if the High Voltage power is too high.

Now power the game on, and test the voltages to make sure they are Ok. First test the HV power at the solenoid driver board's GND and TP2 test points with a DMM. About 160 to 190 volts DC should be seen. If it is more than 190 volts, check TP4 and GND. If TP2 and TP4 are about the same voltage (around 230 volts), the high voltage section of the solenoid driver board is blown. This must be repaired *before* the HV fuse can be reinstalled. Also test all the voltages at the rectifier board again, and verify they are within range.
 
Here's some more info from the guides. Testing at the test points should be easy. That might give me an idea of what's going wrong. I'll start with the SDB (once i get it) and go from there like you said Lindsey (the transformer board tested fine). Here's the info I found for anyone following along with my lousy repair skills ahah.

Rectifier Power Supply Board:

* TP1 = +5.4 vdc (AS2518-18 version), +6.5 vdc (AS2518-49 & -54 versions) feature lamps.
* TP2 = +230 vdc (score displays) with connector J3 attached, 150 vdc with J3 disconnected.
* TP3 = +13 to 16.5 vdc with connector J3 disconnect, +12 to 14 vdc with J3 connected. This voltage will become the +5 regulated voltage.
* TP4 = 5.7 to 7.3 volts AC (general illumination)
* TP5 = +43 vdc (solenoid voltage)
* GND = Ground

MPU board:

* TP1 = +4.9 to 5.2 vdc
* TP2 = +12 to 14 vdc
* TP3 = +21.5 vdc (comes from +43 vdc solenoid voltage). NOTE: If a -133 MPU board (with a 1N4148 diode at R113, as used on Granny and the Gators, Baby Pacman, & Grand Slam), TP3 will read about 5 volts DC.
* TP4 = Ground
* TP5 = +4.9 to 5.2 vdc

Solenoid Driver/Voltage Regulator board:

* TP1 = +4.9 to 5.2 vdc
* TP2 = +190 vdc (but often turned down to 170 volts to increase score display life).
* TP3 = +4.9 to 5.2 vdc
* TP4 = +230 vdc
* TP5 = +12 vdc to 16.5 vdc

Note if TP2 and TP4 are both 230 vdc, then the High Voltage portion of the solenoid driver board is not working and needs to be repaired.

Lamp Driver board:

* TP1 = +4.9 to 5.2 vdc
* TP2 = Ground
* TP3 = (only on AS2519-23 version)

Auxiliary Lamp Driver board:

* TP1 = +4.9 to 5.2 vdc
* TP2 = Ground

Display Driver boards:

* TP1 = +4.9 to 5.2 vdc
* TP2 = +190 vdc
* TP3 = Ground
 
Okay I got the new Solenoid Driver board installed from bstnguy. Game powers up fine now. I tested the rectifier board, the MPU and the SDB ad they all test fine!

Couple issues now though, gotta work through em.

I have a stick switch somewhere as the game just keeps counting points..should be easy to find.

Flippers don't work for some reason. I can use the flipper buttons to change the top lane rollovers , so the cabinet switchs are working, but the solenoids for the flippers aren't firing...any help? Gone to read what it may be.

Really happy I have some major progress. Thanks bstnguy. Just need to sort out why the coils aren't firing for the flippers and I'm golden. The drop target coils all seem to work. It's just the flippers that don't I think.
 
Okay little more progress, I just tested and i have 43 volts at all 3 flipper coils. So they are getting power. I must have a loose connection in one of the wires on the boards. J4 on the SDB possibly or J4 to the MPU?
 
Okay the relay does not pull in at all (I do have a new spare one in
case it needs replacing)

I test cr20 diode and I'm getting +43VDC there so that's good.

Okay I grounded the relay and it DOES pull in when grounded.
 
Replaced Q15 (tip102 drive xsistor) on the SDB. Needed some soldering practice anyhow :) But that didn't fix it. Flippers still don't work. What do you guys think
I should try next? I'm so close i can taste it ==grin== Maybe I have an issue with one of the connectors...sorry for all the posts...just kinda talking myself through this..
 
Okay I got a logic probe from a friend. Never used on though. It has a black lead and a red lead. I'm not exactly sure how or where to put the leads so I can probe the U11 chip.

Red is supposed to go to +5vdc and black to ground.

What settings do I put the probe on?

TTL & Pulse?
 
Ok I'm pulling my hair out :/ Now when I turn it on the center drop
target coils keep firing every few seconds and some sound plays but
you can't start a game or anything. I must have some MPU issues. There
was some shoddy work done on it. Maybe I just need to send it in for
repair. Think that may be my best bet at this point.
 
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