(Topic ID: 330002)

Star Trek : Bally 1979 occasionally restarts. Low voltage issue?

By TurboTJK

9 days ago


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  • 14 posts
  • 8 Pinsiders participating
  • Latest reply 8 days ago by gdonovan
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#1 9 days ago

Star Trek

I own a recently restored Star Trek Bally 1979 game. After a month of inactivity, I turned the game on but it began resetting during play. When the game restarts it goes through the same flashing light procedure that occurs when the power is first turned on. If the game resets, it won't push the ball out of the hole or if it ends up in the trough, it won't push the ball back to the shooter lane. Occassionally, the game won't start at all and stays on the solid green light, when it should dim the green light when it's ready for play.

I had the Alltek Ultimate MPU board installed professionally about 6 months ago and everything was fine, until a few days ago when the resetting issues started happening. I checked the voltage on Test Point 1 (with test point 3 connected to the black sensor) and it read a voltage of 4.80. The manual online says that "Any 5v reading of 4.85vdc or less is something that needs to be repaired"

https://allteksystems.com/apps/help-center#hc-what-is-the-correct-way-to-test-the-5vdc-on-the-ultimate-mpu-board

I've never worked on a machine before, so I'm not really sure where to go from here. Is the low voltage reading from test point 1 actually the problem (I'm only guessing that it is)? If so, how do I go about addressing this?

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#2 9 days ago

It could be a bunch of things, but a few common items to check include bad connectors on the power supply board, cold solder joints on the connector header pins on the power supply or solenoid driver board, or a failing 5V 12000uF capacitor on the solenoid driver board.

#3 9 days ago
Quoted from TurboTJK:

I had the Alltek Ultimate MPU board installed professionally about 6 months ago and everything was fine

Most of these pinball boards are just plug & play. What exactly does "installed professionally" mean in this context? Not trying to be a smart-ass; it's a serious question.

#4 9 days ago

Is the power supply board the one on the upper right of this photo? Is that the same as the Solenoid board? How do I check for bad connectors?

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#5 9 days ago
Quoted from sparky672:

Most of these pinball boards are just plug & play. What exactly does "installed professionally" mean in this context? Not trying to be a smart-ass; it's a serious question.

I've owned this pinball machine for over 35 years and for maybe the last 20, it sat in a basement unplayable. I took it to a pinball arcade and had them fix it up. It turns out the battery leaked onto the old mpu after all that time so they recommended I get (and they installed) the new ultimate mpu board and also a new lamp driver board. The solenoid and sound board I believe are still the original.

#6 9 days ago
Quoted from TurboTJK:

... It turns out the battery leaked onto the old mpu after all that time so they recommended I get (and they installed) the new ultimate mpu board and also a new driver board. ...

Hopefully they did more than simply remove and plug in two new boards. I am not trying to be critical as they may have done a ton of honest work, but swapping out boards takes minimal skill and effort.

Would they be willing to troubleshoot this for you under warranty perhaps?

#7 9 days ago

The board in the top right corner with the two heatsinks is the solenoid driver board. Rectifier board, sometimes called power supply, is in the bottom right corner, above the transformer.

You didn't mention which board you were testing voltages on. Every board in the game has test points. Link below should get you pointed in the right direction. If you don't have a game manual, you can download one at the second link.

https://www.pinwiki.com/wiki/index.php/Bally/Stern#MPU_boot_issues
(note the reset section in the link)

https://ipdb.org/

#8 9 days ago

I tried unplugging the connectors to the rectifier board and plugging them back in again and it started playing through a full game. I wonder if when I took it home the first time I hadn't properly set the connectors tight enough to the rectifier board, and over time movement knocked them out of place. Thanks Eric_S sparky672 phishrace. Hopefully it's resolved for now.

#9 9 days ago

Your solenoid board still has the original electrolytic capacitors on it.
The big one in the middle is the filter for the 5V rail and if it is dying will cause you problems.
There are several Youtube videos on how to replace this and it is mentioned in PinWiki how to do this.
Macro Pinball even sells a kit of the 3 capacitors for the board.
Your board is also missing the perspex cover over the HV section of the solenoid board, so don't got poking your fingers near the top left of the board with it turned on unless you like shocks.
The part number for the HV shield is Bally M-1837 not sure what screws you need to fit it though.
If you still have the original connectors on your wiring they could also be reaching end of life and need replacing which is why reseating them fixed it.
I just picked up one of these machines, but mine needs lots of TLC before I can play it.

#10 9 days ago

Your solenoid driver board (top right) needs new capacitors and ground modifications. The power supply board (lower right by the transformer) needs to be serviced. I see some hacky repair and it probably needs new connector pins. Your sound board (small board lower right under the solenoid driver board) needs new capacitors too.

For reliability, all of these 40 year old components need to be replaced. Pins in the connectors should be replaced too. Some people just purchase new boards. That is great too. But the connector pins should still be replaced. I'm not too far away if you want board work done. Just PM me.

#11 8 days ago

Is there any reason why I shouldn't just buy the Alltek ultimate solenoid board and replace it with that? Would that solve the issue with the old capacitors?

#12 8 days ago

If the batteries on the old MPU puked, it likely corroded several of the pins in some connectors. Contact your professional who installed the Altek board and ask if any connector pins were replaced, especially J4 on the MPU.

When troubles start again, with power off, remove the connectors on the MPU and LDB (Lamp Driver Board) and see if the pins inside the connector have green on them. If so, then you’re seeing corrosion from the original MPU, and needs to be repaired by replacing the pins in those connectors.

As others have stated, the SDB (Solenoid Driver Board) probably needs an update. Yeah, you could buy a new board, but to me, there’s a certain thrill one gets with a successful repair.

Learn a few new skills! You’ll never regret it.

#13 8 days ago

Why not have a go to replace the capacitors and do the modifcations, worst case you damage the board and need to replace it, but if you are already thinking about replacing it then no real loss.
I made a point of not buying a perfect machine as I almost like the job of fixing them up as much as playing them.

If you have some time to (probably over several nights) there is a series of videos on Youtube where an arcade repair shop gets a Bally Star Trek pinball machine that had been shot and left in a falling down house and restored it back to running condition and just about everything needed fixing on it. It's worth watching to have an idea of some of the issues you may come across but hopefully not as extreme.

#14 8 days ago
Quoted from sparky672:

Hopefully they did more than simply remove and plug in two new boards. I am not trying to be critical as they may have done a ton of honest work, but swapping out boards takes minimal skill and effort.
Would they be willing to troubleshoot this for you under warranty perhaps?

1) Any Bally/Stern tech worth their salt would have changed out the 5V cap minimum. minimum.

2) The factory Bally SDB are pretty robust- Change out the 2 caps, a few ground mods, reflow the header pins, check the display volts to make sure they are not out of spec and you are good to go. $10 worth of parts if that.

3) Having to repin the connectors would not be a surprise, 50% of the Bally's I picked up needed the job done otherwise erratic operation is standard.

The connectors are only rated for so many insertions, time and environment takes it's toll as well.

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