(Topic ID: 292210)

Bally Power Module Help Needed - Xenon won't boot

By Black_Knight

5 months ago


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  • Latest reply 5 months ago by G-P-E
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#1 5 months ago

Cleaned up my Xenon the other day, including vacuuming out the cab. It has been flawless for over 5 years, now the machine won't boot, the sound board puts out a howl, and the displays flicker very weak.

Xenon has the power module/ rectifier board in the lower cabinet.

My high voltage DC circuit @ test point 2 is only putting out 152 volts instead of the 220 it is supposed to.
All other test points are good.

I have done the following:

- Checked and cleaned the F2 fuse and fuse holder. I have 0 resistance across the fuse solder joints, so both are good. Also checked the other fuses and test good.
- Tested the 4 Diodes and the resistor, test good. This circuit uses didoes instead of a bridge rectifier
- Tested continuity from both input pins on J5 to the single output pin on J4, multimeter shows 650 and 625 with the diode test, this is close to the individual tests on each of the diode (not sure what that means other than there is a drop in power)
- Visually inspected the transformer and wiring and cannot see anything. The two red input wires are from the input side of the transformer/power line. Can I test these before plugging back in to the power board? Where do I ground them to get a good AC reading?

I am at a loss for what to do at this point. I assume the issue is the high voltage circuit, but any suggestions or help is appreciated.

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#2 5 months ago

I think you’re barking up the wrong tree. The HV section wouldn’t keep you from booting up. Do you get any flashes on the mpu?

#3 5 months ago

I hear ya. Was focused on that board since I hadn't opened the head until after it went bad and the PinWiki steps and it suggested getting the rectifier board working 100% before moving on. I'll skip it for now.

Should have mentioned it's an Alltek MPU board.

I get no flashing on the MPU. Solid Self test light and Solid 5v light. Manual suggest checking 45V if the light is solid, but it checked fine.

The test Points on the MPU are good except for TP5 - VMA, I get 0. This is Valid Memory Address?

On the Solenoid board, I have 12 v and just over 4 v at the test points.

The speaker was a loud low humming, not a howl.

#4 5 months ago

The next step if all your voltages are present is to plug in the solenoid driver board and unplug all the other boards. This is where both the 5v is created for the rest of the boards, and where high voltage is controlled using the pot. See if you get the proper readings here.

This has some great information in it even though this pre dates xenon. The power module and vocalizer board are not included in this but the mpu lamp driver and solenoid driver board are:

http://files.arcadeinfo.de/Anleitungen%20Flipper/Bally%20Electronic%20Pinball%20Games%20Repair%20Procedures%20F.O.%20560-1.pdf

#5 5 months ago

Trying unplugging the sound board and see if it boots.

#6 5 months ago
Quoted from Black_Knight:

I hear ya. Was focused on that board since I hadn't opened the head until after it went bad and the PinWiki steps and it suggested getting the rectifier board working 100% before moving on. I'll skip it for now.
Should have mentioned it's an Alltek MPU board.
I get no flashing on the MPU. Solid Self test light and Solid 5v light. Manual suggest checking 45V if the light is solid, but it checked fine.
The test Points on the MPU are good except for TP5 - VMA, I get 0. This is Valid Memory Address?
On the Solenoid board, I have 12 v and just over 4 v at the test points.
The speaker was a loud low humming, not a howl.

When the game is turned on how many times does the mpu self test flash?

#7 5 months ago

MPU test points are good
Solenoid test points are good (well 4v like noted earlier). Tested this as the only board plugged in and with all boards plugged in.
I Disconnected the sound board a long time ago
No flashes at all, just solid green LEDs on MPU

Thanks for the link, I've been looking for something like that.

#8 5 months ago

So then if the solenoid driver is showing 4v on the test points, that isn't going to boot the mpu. So I would check/reseat J3 on the SDB to see if the voltage improves. If it doesn't then swap solenoid driver boards with a different game to see if it is the SDB. If voltage is still low and the connector J3 has been recently rebuilt, then its the power module.

#9 5 months ago

OK it is 4.3V, but that makes sense.

This is my first bally work and I'm a little confused by the schematics. (williams diagrams of the time are way easier to understand)

The un regulated 5V on the power board is tested at TP 3 @ 12v. It is Pin 10 on connector J3 on the power board. If that corresponds to pin 10 J3 on the Solenoid board, then those connections look good and tight. I'll test it on that end next.

#10 5 months ago
Quoted from Black_Knight:

My high voltage DC circuit @ test point 2 is only putting out 152 volts instead of the 220 it is supposed to.
All other test points are good.

A lot of digital multi-meters will only read around 150V at TP2 on the rectifier board. You can ignore this.

If you're only getting 4V out of the 5V regulator, the DC voltage going into the regulator may have lost its filtration.
Measure the voltage directly on the large C23 filter capacitor on the solenoid driver board: black meter probe on the negative capacitor leg, red meter probe on the positive capacitor leg. You should measure somewhere between 14 - 16 volts DC.

Suggest re-soldering the heat stressed solder joints on the rectifier board at fuse F3 and diodes CR5, CR6, CR7 and CR8.

#11 5 months ago

Ok I cleaned the # 10 pin of J3 on the solenoid board for the 12v input. It is now working. Didn’t notice anything before but it was a little corroded/burnt and none of the others were.

It’ll need repined but works for now. Thx for all the advice.

#12 5 months ago

Common problem for that pin to go bad (my Xenon did this too).
Add three jumpers to bottom of driver alleviate this issue in the future -- especially jumper "B" in your case.

https://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Solenoid_Driver_Upgrades

And definitely re-pin the plug to J3.

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