Gold Ball Pinball Machine (Bally, 1983)

Location: Highlands Ranch, CO.
Symptoms: Wouldn’t boot, rubber rings crumbling.

This machine sat neglected prior to the current owner purchasing it.  Although the NiCad battery looked ok and looked like it had been replaced relatively recently, there was a lot of corrosion on the CPU board.  It was even affecting the RAM sockets, where I could see blue-green corrosion in the socket holes.  During the boot process, the LED would only flash a couple of times, indicating a RAM failure.

Normally I would try to fix something like this.  In this case, since there was an aftermarket CPU board available, I recommended the owner purchase the new board.  With the old board, I could fix one thing, only to learn something else was damaged by the corrosion.  It turned out I was correct, except the corrosion had spread to the sound board, which sits right below the battery.  It had damaged the sockets there as well.

I was able to get the sound board working with some cleaning.

The rubber rings and burned out bulbs were replaced, and the playfield cleaned as well.

Tee’d Off Pinball Machine (Gottlieb, 1993)

Location: Cheyenne, WY
Symptoms: Flipper problem, Spinner problem

It seems like every Gottlieb – Premier pinball machine I work on has over-fused flippers.  The fuse should be 2.5 amps and in this machine there were 5 amp fuses installed.  When the flipper link broke, it caused the flipper arm to not engage the End-Of-Stroke switch, which caused the coil to melt.  Had the correct fuse been installed, the coil would have been saved.

I replaced the coil, the fuse and the broken link and everything is fine with the flipper.

The other problem, and I’ve seen this on a Monte Carlo pinball machine (which is the same vintage) is that the switches on the center spinner don’t work.  In this case, the spinner wasn’t spinning very fast either.  I cleaned and oiled the wiper contacts and the gears.  I checked every hole in the spinner and verified that each switch was working.

Funhouse Pinball Machine (Williams, 1990)

Location: Up Poudre Canyon, west of Fort Collins, Colorado.
Symptoms: Needed to be “shopped” (basic restoration).

This pinball machines gets the award for the worst leaking batteries I’ve ever encountered.

Forgotten batteries causing a lot of damage.

Forgotten batteries causing a lot of damage.  Click for larger.

The corrosion was so bad that the battery holder nearly fell off the board when I started cleaning it up.  The corrosion had eaten through the metal pins that hold the battery holder to the board.  As you can see from the photo above, the corrosion was also affecting the nearby circuitry.

I finished removing the battery holder from the board and flushed the board with white vinegar and scrubbed with a toothbrush.  The vinegar helps to neutralize the alkaline. After letting the board dry out for several hours, it still was able to boot up.  I installed a remotely mounted battery holder on the inside of the backbox, where if the batteries leak in the future, it won’t damage anything.

I “shopped” the rest of the machine, replacing rubbers, cleaning the playfield, and replaced the bad bulbs.  The machine is working great and looking great.  I’ve now worked on more Funhouse pinball machines than any other model, breaking the previous record held by Star Trek: The Next Generation.

 

No Fear: Dangerous Sports Pinball Machine (Williams, 1995)

Location: Castle Rock, CO.
Symptoms: Needed to be “shopped” (basic restoration).

The biggest problem that this machine had, which I’ve come across a lot lately, is forgotten batteries.

Batteries dated 2006 badly leaking and damaging the battery holder and switch connector (not shown).

Batteries dated 2006 badly leaking and damaging the battery holder and switch connector (not shown).

Fortunately, on the WPC-95 systems, the batteries are mounted on a separate piggy-backed board which saved the CPU board from certain death.  But even so, the alkaline affected the cabinet switch connector located right next to the batteries.

The battery holder was removed and the RAM chip at U8 replaced with an anyPin NVRAM module that doesn’t require batteries.

The playfield was cleaned, all of the rubber parts were replaced, as well as the slingshot plastics.  The machine is looking good and playing well.

Terminator 2: Judgement Day Pinball Machine (Williams, 1991)

Location: Castle Rock, Colorado.
Symptoms: Machine needed to be “shopped” (basic restoration).

The owner had just purchased the pinball machine from an acquaintance. The playfield was one of the dirtiest I have ever come across.  Fortunately, with a lot of elbow grease, Novus 2 polish and some Mill Wax, I was able to get the playfield looking pretty good.

To clean the playfield and replace all of the rubber parts, the ramps had to be removed, then replaced.  This is time consuming, but was worth doing.

I installed a new flying hunter killer ship kit for the playfield, since it was missing.

The pinballs were replaced with new ones because the existing ones were badly pitted.  The main reason the balls were badly pitted was that the left side kickback was badly damaged. Each time it would fire, it would slam, metal to metal, against the ball, making small pits in it.  The metal that was on the ball would come off and wear into the playfield.

Damaged kicker on left, new kicker on right.

Damaged kicker on left, new kicker on right.

By the looks of it, this kicker had been broken for years. Never allow any device that comes in contact with the ball to go un-repaired.  The playfield is the most valuable asset in a pinball machine and pitted balls will shorten its life.

The switch on the cannon was intermittently bad.  Usually it’s the wires that have broken after the cannon has twisted them back and forth thousands of times.  But in this case, it was the switch itself.  It was replaced.

It goes without saying that any burned out bulbs were replaced.

By the end, the pinball was playing well and looked great.  Some of the mylar on the playfield is bubbling and that will have to be addressed at some point in the future. The biggest problem with removing it will be that the decals on the playfield inserts will not survive the process and I haven’t seen any decal sets for this machine.

 

Funhouse Pinball Machine (Williams, 1990)

Location: Windsor, Colorado.
Symptom: Dead, with a slight humming sound.

When powered up, a slight humming sound would come from the speakers, indicating that at least part of the machine was getting power. No lights were coming on and the MPU was not booting.

Checking the fuses, I found fuse (F113) bad, which powers the 5V logic circuit.  I replaced the fuse and it blew again within a few seconds.  I unplugged the MPU board and the 5 volt supplies to the playfield.  With my multimeter, I determined a short existed on the power/driver board.  I suspected the bridge rectifier had failed. Checking the rectifier I was able to confirm a shorted diode between one of the AC inputs and the “+” output.

When I removed the old bridge rectifier, it was clear why it failed.  When assembled at the factory, the screw was cross-threaded and the rectifier never made good contact with the heaksink.

Heatsink for bridge rectifiers on the Power/Driver Board.  Left end of heatsink never had a good thermal connection with the rectifier.

Heatsink for bridge rectifiers on the Power/Driver Board. Left end of heatsink never had a good thermal connection with the rectifier.

Lately, I’ve been seeing a number if issues in pinball machines where the problem originated at the factory.  For example, I was recently working on a Bally Scorpion and found a staple in the wire harness on the backbox light board.

Anyway, after replacing the bridge rectifier, the machine powered up fine.

 

Jurassic Park Pinball Machine (Data East, 1993)

Location: Niwot, Colorado
Symptom: Smoke,  GI lights not working, some switches not working

There were a number of burned connectors in the backbox.  There were a couple associated with the GI lighting on the light board and the play field, and another connector on the power supply board.

I was able to re-pin one of the GI lighting connectors and the owner suggested just bypassing (removing from the circuit) the connector for the light board since it was unlikely that anyone would need to take the light board out of the backbox.

Burned connector, CN1, on the power supply board.

Burned connector, CN1, on the power supply board.

The power supply connector was problematic.  I tried several ways to fix it, but it would just heat up and start smoking again.  Part of the problem was the plastic had melted and mixed with the solder, making it very difficult for the solder to stick to the metal.  I decided that it would be best to replace both the PCB mounted connector and its mate.

Fixing the connectors solved all of the power problems.

There were several switches not working.  One had a broken wire.  Another was mis-wired at a connector, making me wonder if it hadn’t left the factory that way.  After everything was fixed, the owner and his son were trying it out and exclaimed they hadn’t seen various modes of the game previously.  It hadn’t been fully working in the 10 or 15 years they had it.

 

Eight Ball Pinball Machine (Bally, 1977)

Location: Highlands Ranch, Colorado.
Symptoms: Display not working, dim playfield lights, needed tune-up and testing.

The player 1 display only had a single digit working (10,000’s).   The first thing I did was swap it with the player 4 display to make sure the problem was with the display and not the MPU board or a connection problem.  The problem moved to the player 4 display after swapping, indicating the problem was with the display board itself.

With my oscilloscope, I verified the signals going to the display and the outputs of the driver transistors.  The other digits were working fine but were not illuminating.  The 10,000’s digit had a shorted transistor (Q11, 2N5401) which kept that digit on all of the time.  Normally, only one digit is turned on at a time, but it is done so fast that the human eye doesn’t detect it, giving the illusion that all digits are on.

In this case, with one digit shorted ON, the other digits stop working.  I’m guessing it has to do with ionization of the neon gas.  I replaced the transistor, and the other digits started working normally.

The controlled lamps on the playfield were dim and when in test mode, the power supply in the backbox would start buzzing when all of the lamps flashed on. I checked the voltage at TP1 and it was around 3V, which is too low.  The symptoms of buzzing and the voltage being about half, indicated a bad bridge rectifier (BR1).  This rectifier fails on many Bally machines of this era.  Once replaced, the playfield lights were at normal brightness and the buzzing stopped.

 

Black Jack Pinball Machine (Bally, 1977)

Location: Cheyenne, WY
Symptom: Wouldn’t boot up.  Battery leaking.

Before powering up, the first thing I did was to remove the leaking NiCad battery from the MPU board.  Fortunately, it hadn’t damaged the PCB traces.  I replaced the RAM with an anyPin NVRAM module.

The machine wouldn’t boot when power was turned on. I checked the power supply first, since the power supplies in this era of Ballys are notorious for failing.  All voltages were good.

The light on the MPU board flashed 7 times on power-up which indicated that most of the boot sequence was executing, but it was stopping just short of going into “Attract Mode”.

With my oscilloscope, I started probing around the MPU board.  The processor was running and there was activity on the address and data buses.  There was no activity on the IRQ (interrupt) line (pin 4 on U9).  There are two sources (that I’m aware of) for interrupts.  One is the display, the other is the AC zero crossing detector.

I checked the display interrupt generator, which is a 555 timer at U12.  There were pulses on pin 3.

Next I checked the zero crossing detector and found no pulses there.  The problem ended up being the 2.0K resistor (R113) at the input to the board, and is the top part of a voltage divider in conjunction with another 2K resistor at R16.  Fortunately, Radio Shack still carries resistors (although the guys working there have no idea what a resistor is or what it does).  We were able to get a 2.2K which is close enough.

Once the resistor was replaced, the machine booted up just fine.

 

Star Trek: The Next Generation, Williams Pinball Machine (1993)

Location: Lone Tree, Colorado.
Symptoms: Kept losing track of balls.

I have worked on more ST:TNG pinball machines than any other model.  Which is kind of cool since it is one of my favorite games to play.

This machine needed cleaning and tuning up.  It also suffered from broken wires on one of the cannons, which is a problem I’ve seen with every ST:TNG I’ve worked on.  The rotation of the cannons causes the wires to flex.  Eventually after a thousand flexes, a wire will break. Somebody should supply replacement wiring harnesses — connectors on one end and bare wires on the other — to make replacement easier.

Usually what I do is identify which wire is broken and run a replacement beside the original harness.  So far, there has always been more than one wire broken.

The biggest problem with diagnosing these broken wires is that when the cannon is sitting in its normal home position, everything is fine.  Usually the wires open when the cannon rotates out to the playfield.  And the problem with the diagnostics is that you can’t test the solenoid, light and opto-sensor while the cannon is moving.

This machine had an interesting symptom where during game play, the ball would load in the the cannon, then it would swing out, but it wouldn’t shoot until it was back in the home position. This would fire the ball back down below the playfield on top of an existing ball.  There is a limit switch that is supposed to keep you from shooting the ball anywhere other than the open playfield. Apparently this limit switch is ignored if the solenoid wires break open when the cannon rotates out.

After I repaired the broken wire to the solenoid, I noticed the cannon was shooting during start-up. This symptom I had learned about on a previous repair.  One of the wires to the opto-sensor was broken.  The machine thinks there is a ball there and tries to get rid of it.

After fixing the cannon, the machine would still lose track of the balls under the playfield.  I discovered the ball diverters under the playfield were sticking.  I cleaned those, as well as the opto-sensors and it seems to have solved all of the problems.

Although the game is working fine, the right outlane switch is bad and will be replaced on a subsequent visit.