All you need to do is remove the ground wire off of each resistor board. That will remove the warming resistor from the circuit without removeing the the droping resistor for the led. There is usally only one ground on each board, put heat shrink on the end and your done.

The ones with two wires are daisy chained from one board to another and both will need to be removed and shrink wraped.

You remove the ground wires, that way no mistakes in removing wrong resistor.

Now wasn't that easy.

The warming of the bulbs makes them get to full brightness quicker, so more like a flash then just turning on. And also increases bulb life because less shock.

Some of the bulbs in that machine are #1251 bulbs. These are 28 volts, #89 bulbs are 12volts. Test the wire on the bulb socket and see how many volts there is.

I don't know of any company making 28 volt led flashers. I think if you put a 1200 ohm 2 watt resistor in line with the #89 led flasher it stop burning out.

A 28 year old machine has a lot of fingers in it. Like I said if you remove the ground wire there is no path for the warming resistor to work and later it can be put back in a minute. This only works on correctly working pins. If your boards don't look factory post a pic so we can see whats wrong with what you have.

You can try replacing the diodes on the flipper coils.

If you get some 1n4007 diodes you can you them on the coils, lamps and switches. You can use them anywhere a 1n400x diode is used.

Remember that they must be installed in the correct direction.