So, I'm on the road, at a bar that has a Funhouse and a KISS game. I play a few games and go back to my laptop. A nosy guy apparently is watching me type and says:

Guy: So you are Vid1900?
Me: Eh, no.
Guy: I recognized Pinside a mile away - you are logged in on it!
Me: Yeah, Pinside is great.
Guy: I'm xxxxxxxx on there, glad to meet you!
Me: (we shake hands)

So we drink and the guy tells me he loves pinball, has 2 non working machines and is looking to buy another.

He wants me to come fix his machines, he lives one block over. I tell him my hourly price hoping to scare him away. I also tell him I'm on the road for work and have only basic parts in my van. He cons me into following him to his house.

His favorite game is Bally Supersonic and he also has an EM with a missing backglass (some kind of western theme).

Inside the cab there are a pile of CPU and Driver boards. I guess somebody decided that it's cheaper to keep replacing them, than to fix them. Two of the driver boards have the same Q3 transistor blown, yeesh.

I cut the knocker out (clipping one coil lead), before it can do any more damage.

The associated 120 and 330 ohm resistors are nicely blackened, as is the 1N4004 diode.

Believe it or not these resistors still test good!

I pulled them and the diode out. Even though they work now, there is no sense in leaving a ticking time bomb.

The TIP102 transistors are much higher rated parts than the originals, always good to have on hand.

The diode has a band on it that has to be installed in the same direction as the original.

RESISTORS.jpg REPLACED.jpg

Any time you have a Bally Driver board out for service, there is some bulletproofing to do.

Job number one, ALWAYS replace the capacitors C26 and C23.

The new caps are always smaller in size, even though I always use higher voltage parts.

Parts made to withstand higher voltages will last longer when used at lower voltages.

C23 was a 11,000uf 20v cap - I replaced it with a 15,000uf 35v unit.
C26 was a 150uf 350v cap - I replaced it with a 150uf 450v unit.

(uf is pronounced "micro farad" )

CAPS.jpg

I can hear you guys now, why replace a cap if it is still good?

Caps have about a 12 year life span, and these caps are almost 3x that age, and have had a very hard life.

Lets look at the 11,000uf unit, C23.

It tests good as a capacitor & it looks good on the ESR meter.

For how long is anybody's guess, but right now it's good.

good-cap.jpg

Now we look at the 150uf cap, C26.

The capacitance reading is good, but look at that high ESR reading!

Your normal VOM meter would have said this cap is good, but the ESR meter tells the whole story. This cap is on its way out.

For reference, the replacement cap had an ESR of .06 ohms.

You can use the ESR test in circuit. I tested these caps really as an afterthought. From experience, I would have replaced the caps no matter the reading.

bad-cap.jpg

Next on the bulletproofing is to tie C26's NEG leg to ground.

These Bally boards had some strange designs and we can make them more reliable .

Note also the completely vaporized board trace. I replaced that trace with a wire, hot glued to the board.

C26-GND-MOD.jpg

We also need to tie C23s NEG leg to ground.

Just scrape off some of the conformal coating and solder in your jumper.

Note the not too bad solder joints on the transistors that have been replaced in the past.

I checked all the transistors on the board before reinstalling it.

C23-GND.jpg

Next we always tie Test Point 1 to Test Point 3.

Otherwise the voltages take a crazy run off the board and back through the connectors.

Before you tie them together, you will see that they are often different voltages.

Don't mix up TP1 and TP5 or you will cause lots of damage!

TP1.jpg

So back to the knocker coil. I sure did not have one with me, and the existing one did not have a diode on it - probably taken from the EM machine next to it.

The coil did not smell burnt.

It did have a puncture through the wrapper that had chipped off the red insulation.

I removed the wrapper and looked at the chip, it seemed that maybe the chip was shorting the coil (the coil resistance was something like 2 ohms).

After snipping the end of the wire off, I unwound the coil until I was passed the damaged part.

Then I scrapped off the insulation and wrapped the bare wire around the lug. I tested the resistance and we had a good coil again.

COIL-REPAIR.jpg

Next I stuck in a new diode and wrapped its legs around the lugs.

I soldered both lugs and the coil was ready for action again.

DIODE-INSTALLED.jpg

So we put everything back together again and played ourselves some Supersonic.

He still needs to install a remote battery holder (I did not have one with me) and needs a new speaker (the old one is completely torn all the way around).

He paid me and gave me all the dead boards from inside of the game (very cool).

Not one of my usual guides, but a good launching point should you have to repair a Bally Driver board.

A little extra effort can go a long way towards Bally reliability.

I know, right?

When I was younger, I dreamed only about Money and Broads.

He was indeed happy. He told me he did not want his name used as I was taking pictures of the repair process. I suspect he was the one that put the EM knocker in, and kept replacing boards - I'm not 100% sure though.

He was a good player, I know that for certain.

If you still need work in about 6 months, PM me. I'm really backed up with working on the road the last few months.

From running a route for so many years, I'm used to doing "on site" service - but nothing beats sitting at a well lighted bench with a complete rework station.

If you are in a hurry, hit up: http://webpages.charter.net/coinopcauldron/brepairs.html

It's a real player's game.

Fast and rewarding.

As electrolytic caps age, their ESR (Equivalent Series Resistance) increases.

The higher the temps and ripple, the faster the caps age.

Of course, the higher the resistance, the higher the temps, so the problem becomes a downward spiral.

As you could see from the C26 example, even though a cap's capacitance value is within spec, the high ESR tells us that the cap is not functioning properly.

99% of the time, the ESR meter can read a cap while still installed in the circuit. Although, when you have a bank of caps installed parallel to each other (like in an unregulated CNC stepper driver power supply), you have to pull one leg.

An ESR meter is not perfect. It will not read really tiny caps (like anything below .01uf), and there is not a perfect go/no-go line. You quickly learn the acceptable ESR ranges for different cap values. Just probing through your junk box will give you a crash course in ESR in about 15 minutes. Bad caps will often just say "Leaky" on the display.

As far as which ESR meter to buy, there are many that cost more than the Atlas ESR70+, but I don't think any have the all the features that it has. If you repair lot's of boards, it is a great tool. If you just poke around a few times a year, you can buy lots of replacement caps for the $129 that the meter costs...

I can't be sure. The guy was a little evasive about history of the game. It worked, then it broke, but it still worked...I could not really nail down the timeline or who worked on it and when.

I'd guess that the old knocker shorted, killed a replacement board, then was substituted with a knocker from that EM (thus no diode), and maybe the lack of diode killed another board or two.

Somehow the knocker coil became damaged with a short in the windings, certainly killing anything in its path. That transistor was cracked wide open.

Here was another fix that I had forgotten I had taken a picture of.

One of the traces from the Q3 transistor had lifted from the heat of too much current being run through it, but it still had continuity.

I used clear nail polish to "glue" it back down to the circuit board. Nail polish dries very fast, so put some under the trace, wait about 20 seconds and then hold it down with the tip of a resistor lead.

Put some polish over the top also, to help insulate it.

The other trace in the picture was not so lucky. It completely burned up.

I use a wire to replace it, and latter glued it down with hot glue.

LIFTED.jpg

Don't be afraid to ask for clarification.

My Ohio dialect does not always translate nicely with the rest of the country.

And of course, sometimes I assume too much and skip the foundation that is required by some readers.

I've not found a better one.

That page leads to the model ERS60 which is below the ERS70.

The lowest price I see on a quick search for the ERS70 is $138 shipped:

ebay.com link: ESR70 Latest Version Peak Atlas In Circuit Capacitor Tester New Meter ESR 70

You are very welcome.

Keep us posted on how your game now works.

C24 is part of the 5v circuit, bottom right of big heatsink.

It is originally an electrolytic style cap, and is often replaced with a much better Tantalum style.

Ha, I've never noticed that!

It is not.

Replace it, unless your old one looks like this:

tant.jpg