Atari Pinball Games - Troubleshooting
Atarians & Airborne Avengers:- These games used "motor" flipper coils and the process to replace the flipper body shell is to loosen the two set-screws that are accessed through the body of the plastic shell at the fattest part of these shells. Counterclockwise to loosen! Then the shell lifts up off the top of the shaft.
Take EXTREME care to only plug the Solenoid plug only into J8 on the MPU - if you plug it into J7 you WILL blow about fifteen ICs and need serious shop repairs (two hours at our shop). If that was the case then you have to replace all the Switch matrix TTL and a couple of others as well, I find you can often identify these with a Diode Check function on the digital meters. A normal gate is something like 0.500 to 0.800 volts relative to common, a bad gate is under 0.500...
Please mark the Solenoid J8, and Switch J7 plugs and the circuit board clearly with coloured tape so no-one will easily mix them up! I can't stress this enough!!!
I also recommend that you change the Solenoid Fuse in the power supply - at the very rear of the machine change Fuse F1(AA, ME, SR)/or F6(Atarians) Solenoids from a 15A Fast Blow (otherwised called a "Never-Blow") to a 5A Slo-Blo.
The problem is the 15A Fast Blow fuse powers ALL the solenoids including the flippers so it needs to be replaced with a 5A Slo-Blo fuse. Then for Middle Earth and Space Riders you find the wire from the positive terminal of the bridge rectifier that does NOT go to the Flipper Control Relay and add a fuse holder there and insert the 2.5A Slo-Blo fuse. The wire you want to fuse (GRN/BLU - Middle Earth) goes to Pin 1 of J21 on the power supply metal panel. Don't put a bigger fuse in, because then if a slingshot or other coil locks on for any reason then you run the risk of burning holes in the motherboard...
For Airborne Avenger (AA), Middle Earth (ME), Space Riders (SR) Time 2000 (T2K) the Solenoid fuse is F1, however the schematics for Atarians says the Solenoid Fuse is F6 - so check that game more carefully to be sure that F6 is actually the solenoid fuse.
One problem with late model Atari Pinball games (Hercules and Superman) is the factories use of a single sided printed circuit board for the Power Supply. (We won't talk about leaky batteries just yet) The common issue that develops over the years is fractures of the traces at the rear of the interconnect plugs (Molex) and the game then fails to work correctly. So a simple check on these machines is to remove the Power Supply board and resolder the pins
Atari Power Supply
Atari Power Supply lifted connector
Atari Power Supply cracked traces - J4 in this case.
Atari replaced the rotary units with regular flipper assemblies and provided kits for operators to do this as the motors broke down. I have a few of these kits left (somewhat expensive) but you can often repair the motor assemblies with a bit of brazing or other repairs as required.
What is your problem? Is something actually broken or is it weak? Weak is a problem with the mircoswitch (EOS) or the resistor or associated wiring to these two items.
As I said earlier, broken parts can often be repaired - if you have a MAPP gas torch you can braze otherwise I would use a bit of silver solder and a regular propane torch. Silver solder is usually strong enough for this repair and you do not need to overhear the metal and risk ruining the strength of the metal - you just need to heat it up enough to melt the silver solder, way below red hot!
(jrr-at-flippers-dot-com for those who do not have their browser set to open their email client)