Tag Archives: factory defect

Flip Flop, Bally Pinball Machine (1976)

Posted on by
Reply

Symptom: Not resetting, only adds players with start button.
Location: Littleton, CO

I’m always very happy when I solve a problem with a pinball machine that its had since it left the factory. This pinball machine would not reset when the start button was pressed. Instead it would add players. I was able to trace the problem to the #8 Cam-stack of switches on the score motor (the 8E normally closed contact to the reset relay coil).  There I found two wires on two leaf switch terminals that had never been soldered.  The wires were folded over the terminal, ready for soldering, but someone on the Bally production line must have gotten distracted. The wires were making a good enough connection for the machine to pass testing and shipped out to the first customer.  It’s unknown how many owners this machine has had over the past 40+ years, but I bet it was having this intermittent problem throughout its life.

I’ve probably come across a half dozen machines that have left the factory with issues. So far the machines have been in above average physical shape because they got pulled out of public service earlier due to their intermittent issues and sold to private individuals.  A few years ago I worked on a Gottlieb Circus that left the factory with a bad crimp pin connection in one of the connectors. The machine was immaculate.

Intermittent issues are very difficult to find, especially if the machine starts working correctly the moment I start tracing the problem. In this case I was lucky and the machine stayed dead until I found the problem.

Circus Pinball Machine (Gottlieb, 1980)

Posted on by
Reply

Location: Loveland, Colorado.
Symptoms: Displays not working, playfield lighting blows fuse.

I was really impressed by how immaculate this machine was.  It looked like it had just been un-crated.  It definitely had low miles on it.  No doubt home-use only.

The interesting thing about the displays is that the credit/ball-in-play display was working, and the score displays were not working.  They were dark/off.  I spent a few minutes looking at the schematic, searching for what was in common with the score displays, and at the same time, not in common with the credit/ball-in-play display.  There was only one thing: the filament voltages for the display tubes.

The score displays run off a 5 VAC filament supply and the credit display uses a 3 VAC filament supply. So I started by measuring the filament voltage at the Player 1 display and sure enough, zero volts.  I lifted up the playfield and found the 5 VAC leaving the power transformer.  So somewhere in between a connection wasn’t being made.

I found the problem at a wire to wire backbox connector. In this case, there was a pin that wasn’t crimped correctly at the factory.

Crimp pin was installed incorrectly at the factory. The wire was inserted too far and the crimp went around the insulation rather than the conductor.

Crimp pin was installed incorrectly at the factory. The wire was inserted too far and the crimp went around the insulation rather than the conductor.

If I held the wire a certain way, the displays lit up.  I replaced the pin with a new one and all was good.

The next issue was that the general illumination lighting on the playfield would randomly blow a fuse.  This is usually caused by a short at one of the sockets.  I checked each socket and found one that had been damaged (right near where the prop bar is used to prop up the playfield). Just the slightest vibration would cause it to short out.  I replaced that socket and one other socket that was marginal.