So you got yourself a classic Bally or Stern pinball machine and you tried to put some LEDs into it.
The General Illumination circuit worked great (the lights that stay on all the time), but all of the inserts and CPU controlled backbox lights (Player 1, Game Over, Tilt.....) rapidly flash on and off! What gives?
The problem is that LEDs only draw 10% of the current that the old incandescent bulbs used to draw. The components on the lamp board don't sense enough current to latch on, so they shut off. Every 8ms, the CPU sends a pulse to turn them back on. This creates a fast flickering that makes the game unplayable with LEDs.
Past solutions were:
1. Replace the lamp driver board with an Alltek "Ultimate LED/Lamp Driver Board" for $100. This board allows you to use LEDs and gives you an entirely new lamp driver board. If your old board is missing, hacked up, burnt or corroded, this is still your best option. Lifetime warranty too.
2. Add a resistor to each lamp socket. This inexpensive ($2.00 for 100 resistors) fix is where you solder a 470 ohm resistor to each lamp socket under the playfield so that the lighting circuits see enough current draw to stay latched on. Although inexpensive, this fix might take 4+ hours of mindless soldering; and if the old sockets are corroded, it can take a lot of brushing, flux and heat to get the solder to stick.
(pic stolen from Jags)
So Hans at Siegecraft came up with 3 small daughter boards that attach to the original Lamp Driver Board.
These boards have the resistors built in, saving you many hours of work.
At $45 for a entire kit, this can be a nice money saver; especially if you have a bunch of games to convert.
Jump ahead in this post to the -52 Aux Lamp Driver adapter: