Need Help Debugging Power Supply and Shaker

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cap
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Need Help Debugging Power Supply and Shaker

Postby cap » Tue Jul 10, 2018 7:40 pm

The shaker motor in my LAH is not working. After some debugging, I found I only have 0.35V on the Power Supply Board CN1P10 and CN1P11 when it's supposed to be 9V.
Those pins are directly connected to the shaker motor board. There might be other problems but let's start with that one.

The shaker motor is in the lower left on page 50 and the power supply is on page 59 of https://www.ipdb.org/files/1416/Data_Ea ... ics_BW.pdf

I'm confused if CN1P10 and CN1P11 are input or outputs of the power supply.
I took the PS board out assuming 9V was an output and I started measuring stuff.
The bridge DB1 looks OK. Connectivity of the parts up to the current rectifier IC looks OK.
D2 and D3 are wierd, I measure 0.6V in one direction and 2.5V in the other direction though that is in-circuit.
C1 is 49uF which matches 47uF on the packaging but the manual says 330uF
C7 packaging says 33uF when the manual says 330uF. My multimeter is too cheap to measure anything on C7.

Can someone tell me if I found real problems or how to continue debugging this?
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Re: Need Help Debugging Power Supply and Shaker

Postby sylvain » Tue Jul 10, 2018 8:22 pm

What AC voltage (not DC) do you measure between CN1-P10 and CN1-P11 ? Around 9V AC on the power supply?
What about on the shaker motor board, between J1-P1/2 and J1-P4/5? Should be also approx 9VAC.

I assume you already checked the two 2.5A fuses.

Did you check the 1/2 to 1 ohm resistor just before the + terminal of the shaker motor? I do not know how accessible is that component.

Finally, what if you ground the BRN/GRY wire J1-P6/7 on the shaker motor, does it start the motor?


These tests will guide you towards power supply troubleshooting, motor, or drive (Q4/Q23).


Good luck / Bonne chance!
-Sylvain.
Looking for Bally Star-Jet, Capersville or The Wiggler, Williams Magic City, Grand Lizard, Swords of Fury, 1986 Pinstar Gamatron, and a few others.
Collecting & repairing electro-mechanical and solid state pinball machines with quality and care for over 35 years.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Tue Jul 10, 2018 8:49 pm

Duh, I indeed measured in DC. I'll have to put the board back to measure it again.

Yes, I tested all the fuses on the shaker motor board and the PS board.
The 1/2 to 1 Ohm resistor is a large ceramic resistor on the shaker motor board and it reads 1.5 Ohm.
I also tested Q23 in diode mode and it looks fine. I'm not sure where Q4 fits in this.

I'm confused why I should measure between CN1P10 and CN1P11. I would assume I would need to measure between CN1P10 and CN1P12 or any ground; then compare between CN1P11 and CN1P12 or any ground.

I wish I would have thought to ground J1P6/7 on the shaker motor board.
I will try again and report back how it goes.

Thanks for the insights.
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Re: Need Help Debugging Power Supply and Shaker

Postby sylvain » Tue Jul 10, 2018 9:07 pm

You need to measure the 9VAC between CN1-P10 and CN1-P11, and not with any reference to ground:
because this raw AC voltage originates from a secondary winding from the power transformer (via the power supply board), and not in reference to ground...
Looking for Bally Star-Jet, Capersville or The Wiggler, Williams Magic City, Grand Lizard, Swords of Fury, 1986 Pinstar Gamatron, and a few others.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Tue Jul 10, 2018 10:23 pm

I measure 20VAC between P10 and P11. About the same between P1 and P4 on the shaker motor connector.
That seems far from the 9VAC pictured in the manual.

Grounding J1P6/7 on the shaker board did not do anything. Similarly, grounding the pins on J2 also did not do anything. J2 is not pictured in the diagram. It has the actual wire to and back from the motor.

I made a 12VDC battery with 8 D batteries and plugged it directly on the motor and it turns.

Tomorrow I will take the shaker motor board out and check its connectivity.

Your help is really appreciated.
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Re: Need Help Debugging Power Supply and Shaker

Postby sylvain » Tue Jul 10, 2018 10:43 pm

Next step:
- Measure the DC voltage between one end of the large ceramic 1/2 to 1 Ohm resistor on the shaker motor board, and ground.
Repeat the measurement between the other end of the large ceramic 1/2 to 1 Ohm resistor on the shaker motor board, and ground.
In both cases, it should be close to +12VDC (with the motor not running).

Again, this assumes the two 1N5404 diodes are good, contacts good in the CN1-P10 and CN1-P11 connector (e.g. no cold solder joint),
good contacts J1-P1/2 and J1-P4/5 on the motor board, with good 2.5A fuses, along with a good power resistor and solder joints under.

Bonsoir et bonne chance!
Looking for Bally Star-Jet, Capersville or The Wiggler, Williams Magic City, Grand Lizard, Swords of Fury, 1986 Pinstar Gamatron, and a few others.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Thu Jul 12, 2018 10:47 pm

I tested the resistor and it reads 9VDC on both ends. Can you really produce 12VDC from 9VAC with that simple circuit?
I took out the shaker board and the resistor had a broken solder under the board.
I fixed that and now the motor turns but it is very weak.
I only have one machine with a shaker, so I can't try with another motor.
What else can I try?

[EDIT] when I shorted P6 with ground, it made the motor turn strong enough.
[EDIT2] I found Q4, it is on the PPB board. I also found the real Q23 on the CPU board. Warning: some of the LAH schematics are actually documenting JP instead, Dino Eject ain't for LAH.
I will test the little circuit with Q4 and Q23 this week-end and report back.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Sun Jul 15, 2018 10:50 pm

The manual shows Q4 on PPB board but that should be Q2.
I connected CN12P9 on the CPU board to ground and the shaker turns. I believe that means the PPB board is probably fine.
I took the CPU board out and tested Q23 and it seems fine though it could fail under load. R66 is fine also.
I tried testing Q15 in circuit as well but I get crazy readings. I get similar crazy readings for Q15 to Q22, so that test is inconclusive.
My diagnotic is: Q15 or Q23 is bad

Next, I need to diagnose why the coil for the crane ball lock is too weak.
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Re: Need Help Debugging Power Supply and Shaker

Postby sylvain » Tue Jul 17, 2018 7:57 pm

You are doing well up to now.
I unfortunately do not have much spare time these days, long work hours have re-started at the office.

Before proceeding with troubleshooting transistors or component replacement any further - are you saying the shaker motor turns weakly when activated, but strong if you ground pin CN12P9 on the MPU?

If so, this 'smells' like improper bias to me, e.g. the pre-drive transistors common return line might not be grounded properly on the MPU.
Check for proper CN13 connector connection to ground on the MPU, this is a small 4-pin connector. Make sure the board has its screws securing it to the grounded backbox too.

I assume it would be rare to have a pre-driver fail such as Q15/Q23, but possible.
For the weak crane coil, compare its coil number to the number shown in the manual - in case someone had replaced it with the improper replacement...

Bonne chance!
-Sylvain.
Looking for Bally Star-Jet, Capersville or The Wiggler, Williams Magic City, Grand Lizard, Swords of Fury, 1986 Pinstar Gamatron, and a few others.
Collecting & repairing electro-mechanical and solid state pinball machines with quality and care for over 35 years.
Serious and fun hobby, powerful nostalgia !

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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Tue Jul 17, 2018 8:46 pm

sylvain wrote:Before proceeding with troubleshooting transistors or component replacement any further - are you saying the shaker motor turns weakly when activated, but strong if you ground pin CN12P9 on the MPU?

If so, this 'smells' like improper bias to me, e.g. the pre-drive transistors common return line might not be grounded properly on the MPU.
Check for proper CN13 connector connection to ground on the MPU, this is a small 4-pin connector. Make sure the board has its screws securing it to the grounded backbox too.

I assume it would be rare to have a pre-driver fail such as Q15/Q23, but possible.
For the weak crane coil, compare its coil number to the number shown in the manual - in case someone had replaced it with the improper replacement...


Yes, that's exactly what happens, the shaker motor turns weakly when activated, but strong if you ground pin CN12P9 on the MPU.
The MPU board is secured by only 2 screws. I'll have to find more. In fact all the other boards are also missing screws.
A handful of pre-drive transistors were repaired before, including Q23. That part of the board ain't pretty. The smaller tansistors appear original though.

I'll follow your suggestions and report back my progress later this week.
You are so helpful. Thanks^10^6
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Sun Jul 22, 2018 10:42 pm

sylvain wrote:You are doing well up to now.
I unfortunately do not have much spare time these days, long work hours have re-started at the office.

Before proceeding with troubleshooting transistors or component replacement any further - are you saying the shaker motor turns weakly when activated, but strong if you ground pin CN12P9 on the MPU?

If so, this 'smells' like improper bias to me, e.g. the pre-drive transistors common return line might not be grounded properly on the MPU.
Check for proper CN13 connector connection to ground on the MPU, this is a small 4-pin connector. Make sure the board has its screws securing it to the grounded backbox too.

I assume it would be rare to have a pre-driver fail such as Q15/Q23, but possible.
For the weak crane coil, compare its coil number to the number shown in the manual - in case someone had replaced it with the improper replacement...

Bonne chance!
-Sylvain.


I finally had time to buy more screws today.
Earlier this week I tested connectivity on the MPU board between the transistor emitters and ground and all was fine.
I put back the MPU board in the machine with a complete set of screws.
Tried again, same result.

I connected CN12P9 to CN13 (Coil Ground) and the shaker turns quickly. I conclude the ground on CN13 is fine.
I connected Q23's emitter to CN13, activated the shaker in test mode, same weak motor. Connectivity of the emitter to ground is not the culprit.
If I accidentally touch the source of the transistor, the motor spins fine.
I conclude Q15 is fine and Q23 is bad.

For the crane lock coil, there are no numbers on the coil. The coil wrapper is made of cloth. The whole assembly looks legit when I compare against the picture at marcos.
https://www.marcospecialties.com/pinbal ... 15-5889-00
I connect CN11P5 to ground and the crane coil activates but it is still weak.
I connect the non-banded side of the diode on the coil to ground and the coil activates but it is still weak.
Marcos says the coil should be 50.2 ohms. I measure 52.4 ohms for the coil.
When I look at my coil assembly, it looks more like the manual with the top plate flat.
When I look at the marcos picture, there is a bend in the top plate.
I think I will take out the coil lock assembly to see what happened to that plate.
That bend allows the top plate to be closer to the electromagnet which might be all that's needed.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Thu Jul 26, 2018 11:08 pm

I bought a transistor and replaced Q23. Time to celebrate victory with my first board repair....
Nope. Shaker is still too weak. I should have heard the sound of experience talking.
sylvain wrote:I assume it would be rare to have a pre-driver fail such as Q15/Q23, but possible.
This 'smells' like improper bias to me

I started debugging again and went up the chain. I finally found pin1 of resistor array RA9 is disconnected from the last pin.
Final diagnostic: RA9 must be replaced.

For the crane lock, there were some marks like someone tried to flatten the top plate before.
Maybe because the bottom support was sagging and the pin was not high enough anymore.
I bent the top plate like the assembly marco is selling and that fixed it.
For good measure, I also bent the bottom support up a little.
Now the pin moves correctly and fits nicely in the middle of the crane hole.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Mon Jul 30, 2018 8:59 pm

I must ask for help once again because I ran out of ideas.

When I removed the board and tested RA9 again, pin9 was fine. So I did not change RA9.
I swapped the 7408 ICs because they were socketed and the shaker is still weak.
I changed Q15 just in case and the shaker is still weak.
I previously changed Q23 so I did not change it again.

Remember when I ground CN12P9, the shaker is strong.

RA9 is indeed connected to the base of Q15 (the manual says RA7 but that's a cut'n'paste error). RA9 is 564ohms which matches the manual 560ohms.
RA25 is indeed connected to the base of Q23. RA25 is 2.1K whereas the manual says 2.7K
The emitter of Q23 is indeed connected to the solenoid ground.

The schematics is on page 57 of https://www.ipdb.org/files/1416/Data_Ea ... ics_BW.pdf
(that's page 9 of the PDF)

Can somebody suggest how to debug this further?
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Mon Jul 30, 2018 8:59 pm

I must ask for help once again because I ran out of ideas.

When I removed the board and tested RA9 again, pin9 was fine. So I did not change RA9.
I swapped the 7408 ICs because they were socketed and the shaker is still weak.
I changed Q15 just in case and the shaker is still weak.
I previously changed Q23 so I did not change it again.

Remember when I ground CN12P9, the shaker is strong.

RA9 is indeed connected to the base of Q15 (the manual says RA7 but that's a cut'n'paste error). RA9 is 564ohms which matches the manual 560ohms.
RA25 is indeed connected to the base of Q23. RA25 is 2.1K whereas the manual says 2.7K
The emitter of Q23 is indeed connected to the solenoid ground.

The schematics is on page 57 of https://www.ipdb.org/files/1416/Data_Ea ... ics_BW.pdf
(that's page 9 of the PDF)

Can somebody suggest how to debug this further?
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Re: Need Help Debugging Power Supply and Shaker

Postby sylvain » Tue Jul 31, 2018 10:23 pm

Have you tried checking or replacing Q4 (or Q2) TIP36C drive transistor, and checked its associated R16 and D18 yet?
There does not seem to be much else left...
Looking for Bally Star-Jet, Capersville or The Wiggler, Williams Magic City, Grand Lizard, Swords of Fury, 1986 Pinstar Gamatron, and a few others.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Wed Aug 01, 2018 12:22 am

sylvain wrote:Have you tried checking or replacing Q4 (or Q2) TIP36C drive transistor, and checked its associated R16 and D18 yet?
There does not seem to be much else left...


I will try that but I don't understand how that is consistent with grounding CN12P9 making the shaker strong.

I just noticed the pinout of a tip122 is unusual. What really happens is grounding Q23's middle pin (the connector) makes the shaker turn strong.
That's to be expected because Q23's connector is connected directly to CN12P9 and we know grounding that pin makes the shaker strong.
It also by-passes both Q15 and Q23 making those prime suspects.

I also verified the connector CN12 by pulling it and making the contact myself between the connector and the header pin. Shaker is weak. Connector CN12 is probably not the cause.
I also verified the trace between the header pin and Q23's connector by pulling the connector and making the contact myself. Shaker is weak. That trace is probably not the cause.

Describing all this, I got the idea to try to by-pass Q15 by connecting R66 directly to RA25 pin 2.
Will anything bad happen if I also bypass RA25 and connect R66 directly to Q23's base?
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Thu Aug 02, 2018 12:11 pm

I pulled the and-gate IC, that makes RA9 a pull up resistor that activates Q15. The shaker is strong.

The ground is good on the and-gate IC.
That means the problem is in the and-gate IC, the PIA, their sockets, the 5V or the traces between them.
I already swapped the and-gate IC, so I'll look for the other suspects first.
Last edited by cap on Thu Aug 02, 2018 11:09 pm, edited 1 time in total.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Thu Aug 02, 2018 11:09 pm

It is still a mystery.

5V at the PIA and the and-gate ICs are all connected.
Ground at the PIA and the and-gate ICs are all connected.
Voltage between 5V and GND is 4.8V

I had the idea to unplug CN12 and connect CN12P9 to another header pin with aligator clips.
For example, the shaker on P9 is coil #16, if I connect CN12P9 (in the connector) to CN12P8 header pin (on the board), the shaker should activate when I test coil #15.
The shaker activates but it is weak for coil #16 to #11 and #9.
When I connect CN12P9 to CH12P3 header pin (the one for coil #10), the shaker is instantly activated and it is strong.
There is no coil #10 in LAH, so maybe this is normal.

I didn't continue with CN11 since that circuit goes through an extra flip-flop IC.

All the and-gates and all the transistors have the same problem.
It's probably something earlier or more systemic.
The next step is to test the PIA or find what's special about coil #10.
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Re: Need Help Debugging Power Supply and Shaker

Postby cap » Fri Aug 03, 2018 9:44 pm

Blanking on pin 5 of the 7408 at 1J is 4.8V
If I short pin 4 and 5, the and-gate triggers and the shaker is strong.
That means everything from the and-gate and beyond is probably OK.

When I activate coil #16, pin 5 of the 7408 goes from 0.02V to a fluctuating 1V. This is not enough to activate the and-gate steadily.
This is obviously my problem, but what causes it?

Pin 5 of the 7408 comes directly from the PIA pin 17. I find the same voltages at pin 17 of the PIA.
I concluded the PIA is bad. I swapped the two socketed PIAs and tried again. The shaker is weak.
VCC at Pin 20 and GND at Pin 1 look good on the PIA.
Now I'm totally confused: either I have 2 bad PIAs, or something else is going on.

I'm stuck again. If you have an idea for something else to try, I'd like to hear it.
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