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?
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)

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sylvain
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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.
Serious and fun hobby, powerful nostalgia !

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cap
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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.
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)

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sylvain
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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.
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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cap
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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.
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)

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sylvain
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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.
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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cap
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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.
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)

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cap
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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.
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)

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sylvain
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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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cap
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Posts: 633
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Location: Laval

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
Last Action Hero, Rocky & Bullwinkle, Stargate, F14 Tomcat (in restoration)



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