Tech: Bally power supply questions

Greenacarina

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Nov 13, 2012, 3:57:55 PM11/13/12

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I am fixing up a couple games that use the 2518-54 power supply. Both seem
to be having the same "issue"....
At test-point 2 I am getting 185 volts...both boards, both machines. All my
previous experience with these games as been the older style power supply
(Evel Knievel, Strikes and Spares, etc...) and I would think the voltage
readings should be the same (since the games share all share the same
boards, displays, etc...).
If I was getting this reading with just one board or just one machine, I
might suspect a transformer problem or a problem with the board...but now I
am somewhat stumped.
The games I am working on are Speakeasy and EBD. I bought both as "basket
case" projects and have never seen either up and running.

Thanks,
Chris

seymour.shabow

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Nov 13, 2012, 4:31:36 PM11/13/12

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No, the test points can and are different between the -54, -18, and -43
rectifier boards. The boards are all the same, except for the power supply.

The chances of you having 2 bad transformers is very slim.
Additionally, the -54 board is really robust and usually doesn't have
too many issues.

ValidPowerDetector

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Nov 13, 2012, 6:37:15 PM11/13/12

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I have several games with this pwr supply.
175-195vdc is not unusual, remember there is
no regulation there. Components vary in operation.

All the way down to 160v will run the displays quite
nicely. Better where you are, than too much voltage.

AVP Pinball Division

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Nov 13, 2012, 10:03:14 PM11/13/12

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"Greenacarina" <greena...@comcast.net> wrote in message
news:k7uc8h$c20$1...@dont-email.me...

Test point 2 is the -regulated- output voltage. 190 volts is factory spec
but 180~190 is good. Don't go above 190 volts as the insulation in the
displays will break down. This causes segments to mottle and burn-through,
eventually overloading the high-voltage regulator circuit. The regulator
fails in full-on mode. When it goes the displays receive the full 245
volts. The displays begin to toast in a relatively brief period of time
after that.

--
Pistol Pete
AVP Pinball Division
Towson, MD
410-583-9200
web: http://www.AVPpinball.com
email: ser...@AVPpinball.com

KenH

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Nov 14, 2012, 1:55:33 PM11/14/12

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>
>
> Test point 2 is the -regulated- output voltage. 190 volts is factory spec
>

TP2 is the regulated output on the SDB, not the power supply board, right? Isn't TP2 the unregulated output when measured on the power supply board?

barakandl

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Nov 14, 2012, 2:20:30 PM11/14/12

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I am confused. TP2 on which board

TP2 on -54 rectifier = 230v unregulated display voltage (should match
TP4 on driver) Bally says this voltage can vary 25 volts up and down,
and it does. Even more so if it has a load or not.

TP2 on driver = 190v regulated and is what gets pumped to the
displays. This voltage can be adjusted via the pot on the driver
board. I usually set them about 175v. Be careful playing around up
there, i have zapped my self through test leads leaning on the side
rail grounding myself.

If you can not adjust the voltage on the driver board via the pot.
First suspect the pot. Measure its resistance as you change the pot,
if it does not move smoothly replace it. If it is not the pot and TP2
= TP4(230v) on the driver board. Replace all three transistors, check
the resistors in the HV section too as they like to go super nova.