The Shadow Pinball Machine, Bally/Williams

Location: Erie, Colorado.

Symptoms:  Neither ball diverter was working, drop targets on mini-playfield were sticking.

The ball diverters at on the left and right ramps were simply loose on their shafts.  I tightened up the set screws on the left diverter.  The right diverter was binding a little after tightening the set screws and I determined the arm was slightly bent.  I straightened it and it worked fine.

Right ramp diverter, with rings on either side. (Photo from ipdb.com)

I removed and cleaned the drop targets from the mini-playfield.  They had been lubricated with white lithium grease, and as usual, it had dried and was causing them to stick.

I looked at the Test Report and it reported that the switch on the main playfield drop target was not working.  It was simply a case of the drop target sticking and never engaging the switch.  I removed and cleaned the drop target.

There were a couple of broken wires that I re-soldered to their correct locations; one was a flasher and the other a GI bulb.  I replaced 24 bad bulbs. There are four rings with lighted jewels incorporated into the playfield (see photo above).  They are illuminated with a grain of rice lamp that is hard-wired.  Three of those lights on this machine are out.  Marco has these and will order.  I’m guessing they are glued in place.

The machine also needs a new set of pinballs.   Any pinballs that don’t look shiny and new should be replaced on any machine in order to keep the playfield in good condition.

All in all, just routine maintenance.

Judge Dredd Pinball Machine (Midway/Bally)

Location: Denver, CO (Arvada)

Symptoms: Flipper was stuck, multiple connection problems, neither slingshot working.

Stuck flipper: The flipper was stuck because the end of stroke (EOS) switch was broken exactly at the flipper’s maximum travel point.  The flipper wouldn’t return because it was getting hung up on the broken contact.  For a quick fix, I put a piece of shrink tubing over the end of the contact to lengthen it.  As the tubing cooled, I flattened it with my fingers, which basically made a plastic extension for the contact.  Eventually the switch will need to be replaced, but for now it is working fine.

Connection problems:  There were some connection problems causing balls to be continuously delivered to the shooting lane.  Taking a look at the switch test diagnostics, I determined a whole “row” of switches was shorted to ground (row 4).  After checking every switch location in the row on the cabinet and under the playfield, and not seeing any obvious shorts, I decided to look at the back box.  There I discovered if I pressed on the lower corner CPU, the short would go away.  My initial assumption was that it was something on the CPU board shorting out.  Yet, when I unplugged J212 the problem would disappear.

J212

Row 4 is the end pin on the connector (pin 8). So why does lightly pressing on the CPU board cause something associated with J212 to short/unshort.  I looked all around and traced the wires back and couldn’t see anything.  Unfortunately, I moved something and the short went away and never came back while I was at the customer’s site.  After I left the short returned. On a subsequent visit, the problem had gone away again and couldn’t be found.

Slingshots: The owner didn’t realize that neither slingshot was working.  Both had broken mechanical links from the plungers, one had a broken arm.  Replacement parts were ordered and installed.

Doing one last check of the Test Report, I saw that the EOS switch on the left upper flipper was disconnected.  I found the broken wire and resoldered it to the switch.

The Test Report also revealed that one of the ball trough opto switches wasn’t working.  Using a cell phone camera, which can see the infrared light of the opto switches, I determined that one of the IR LED’s was not illuminated.  I checked continuity and didn’t find any problems with the circuit board.  The LED was burned out.  After a discussion with the owner who assured me that the game is working fine, we decided to leave it as is.  There are 7 opto switches monitoring the ball trough and it was of the ones in the middle.  My guess is since the CPU knows it’s bad, it can work around it.  If it causes a problem, there is a very nice after-market IR LED board available which has several design improvements.

And finally, the entire game had intermittent power.  I quickly determined that the line cord was not plugged securely into the rear of the game.

Other than just a few test games, I’ve never played Judge Dredd.  It seems like an interesting and challenging game.

This post has a follow-up here.

Sega South Park Pinball Machine

Symptom: It would shoot two balls into the shooter lane.

At first look, the playfield switch in front of the plunger was badly bent and not reliably sensing a ball.  I assumed this is why it was loading the shooter lane with two balls.  As I tried to straighten out the switch wire, it broke.  I repaired the switch with some piano wire (I guess it’s steel wire) that I obtained from McGuckin’s Hardware store, and epoxied the wire on to the switch lever.

As I investigated further, I discovered the reason the switch wire was bent was because the one-half of the fork was broken off the auto launch kicker (500-6091-00).  When ever the auto launch mechanism shot the ball, it would jam the ball sideways.

Broken Auto-Launch Kicker

Broken Auto-Launch Kicker

 

I found the broken piece down in the bottom of the cabinet. The owner took it to a nearby muffler shop and they welded it back together.  With the switch replaced, and the arm welded back on, I fired up the machine to find it still deposited two balls into the shooter lane.  The playfield switch was functioning correctly.  After another 15 minutes, I realized there were 6 balls loaded into the machine, when there should only be 5 balls.  It never is what you think.   The other stuff needed repairing even though it wasn’t the original problem.

Replaced many bulbs.

Location: Superior, Colorado

Rocky & Bullwinkle and Friends, Data East Pinball Machine

Symptoms:  Stuck flipper, flipper fuse blown, many lights not working.

The flipper circuit uses two voltages, one for pull-in (50V) and another for hold (8V).  The transistor controlling the pull-in voltage (Q9) was shorted, leaving the high-power on to the coil, blowing the fuses.  Replaced the transistor and the flippers worked.

I replaced many burned out lights.  There are two rows of lights (in the 8×8 grid) not working.  The transistors looked fried, and it looked like the board had also been hacked.  Many GI lights on the backbox were not working too.  Someone had re-wired some of the GI lighting bypassing one of the boards.  Some of the ramp diverters are not working, so you never get the Hat Trick. The owner was not interested in fixing these issues!  The machine needs to be “shopped”, but it is still being used in a bar.

Location: Denver, Colorado.

 

The Simpsons, Data East Pinball Machine

Symptoms: Turbo bumpers not working, blowing fuses. Broken wire under playfield, loose playfield components, stuck switch on left slingshot, lights not working.

Machine needs to be “shopped” as it’s not in good working condition.  Found shorted transistor that drives solenoid for turbo bumper.  Replaced it, but it immediately smoked.  Took a closer look at both the input and output sides of the drive transistor (TIP122).  On the output side, discovered a melted solenoid under the turbo bumper.  Replaced the solenoid.  The bumper switch was ok.  Checked the input side of the drive transistor and found the 2N4401 was shorted as well as the 7402 NOR gate IC was blown.  Replaced all the bad parts.

The stuck switch on the slingshot was because the entire slingshot assembly was ready to fall off the playfield.  Tighten it, repaired the broken wire.

Replaced many burned out bulbs.  Backbox lights not working.  Owner didn’t want those fixed.

When playing a test game, right flipper was getting stuck.  The flipper shaft bushing didn’t have any screws holding it to the playfield.  Found enough screws lying in the bottom of the cabinet to fix it.  Flipper was still sticking.  Took it apart to find someone had greased the flipper solenoid.  NEVER DO THIS.  Went through and tried to clean up all of the grease.  Flipper worked fine after that.  Overall the game is working.  It is in a bar.  The owner doesn’t want anything else fixed.

Location: Denver, Colorado.