To prevent the flashers from staying on...? Resistors shouldn't cause that. Also I would NOT do this as it will blow flasher bulbs faster and possibly damage flasher circuits.

Crash didn't the resistors on those games "pre-heat" the filament very slightly (dim red glowing filament) so that the flashers would 'slam' on when they were activated? Either way, I'm not sure why you'd want to remove them? You shouldn't be seeing any light from the flasher when it is not active (unless you take the cap off and stare closely at the filament).

Ah ok, didn't realize you had LED's. Disregard.

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.

The resistor boards have 28v going to them and removing them might cause the flashers to blow, I had the same thing with my pinbot, the new led flashers I installed would stay on at all times, so I put the 89 bulbs back in.
Im no pro... let us know if it works I'd like to do the same to my flashers.

you can either remove one of the resistors, i don't remember which, or just leave one standard in each group. The incandescent will eat the warming current and the LED's won't come on unless they are called.

You only remove the 330 ohm resistors, the other ones are necessary for the flasher circuits to work properly.

No worries, go ahead and remove the warming resistors. The flasher LEDs can handle it...

Either removing the ground wire or one leg of the 330 ohm resistor will do, whichever is easier for you.

If you remove the ground and there are 2 wires connected at that spot, be sure to keep those 2 wires soldered together and insulated with tape or heat shrink tubing so whatever the ground wire leads to, is still grounded.

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

Sigh, so much confusing information...

Read this.. http://techniek.flipperwinkel.nl/wms11/index2.htm#flash

Then you have 2 choices if you wish to use LED flashers.
1. You remove the 330W resistor (lifting a leg is fine, remove the ground wire is fine) or,
2) You leave incandescent flasher in the backpanel and only do the upfacing ones on the playfield.

I did #2 to my F-14.

What is happening is that 330ohm resistor is causing a constant current drag to ground while the lamp is off. This in turn cause a small amount of voltage to be present at the point where the 2 resistors are tied to one leg of the bulb. This in turn causes the bulb to 'warm' or be in a state not off but not on enough for you to see it. That way when the logic says FLASH, the bulb is already half way there.

The resistor does not limit voltage and removing it will hurt nothing even with incandescent, however regular bulbs will ramp up and down and not be as flashy. Not what you want from a flasher.

The reason you have to take it out is the LED bulbs are either on or off, not warm, and that small voltage being placed at the mid point between the 2 resistors is causing LED bulbs to be ON.

The reason option #2 works is because for every flasher on the playfield, their is another 'paired' with it on the backpanel. And that 1 incandescent has enough load to pull that small amount of voltage the 330ohm resistor is causing down low enough that the net result is its LED partner stays off.

I use option 2 all the time, that way 0 mods to the machines wiring. It works on DE/Williams/Bally and any machines with 'paired' flashers.

this one is cake. Simply remove the 330 ohm warming resistors from all of the individual boards. These can stay off the game even if you put incandescents back into the game. Williams got rid of the warming resistors starting with Big Guns yet they didn't change anything else in the circuits. They moved all the resistors to 1 board and then a couple games later they put them all on the interconnect board.

The trickier problem is when putting flashlamps into games that had the Aux power driver board (again starting with Big Guns ). On those games if you put LED flashlamps into circuits #3, 4, 6 or 7, those flashlamps will go off anytime you hit the flippers or any other 50 V coils. On those circuits you would need to cut diodes 3,4,6 and 7 off the aux driver board and then install diodes on coils #3,4, 6 and 7.

BTW, the 330 ohm resistors are the smaller ones (they are only 7Watts and the 5 ohm resistors are a larger 10watt)

You wont see the incandescents with the leds in the clusters. You just need to remove the 330s like stated. Never heard of taking off the grounds. That would seem to break the whole circuit.

AH HA! I always wondered why I never had any trouble when I put in leds in the play field flashers only, that was an old mystery of mine you solved.

Now wasn't that easy.

yup... it is one of the best feelings there is...

Congrats on the Mod!

Yep, no better feeling than successfully doing it yourself! The misc. repairs are part of what makes pinball fun for me!

So there must be a seperate always on circuit to warm the flasher filaments. Why did Williams remove this from newer System11 and WPC machines? Was PWM used later on to preheat the filaments with low voltage?

They got rid of it because they didn't need it. Just like how Atari had a prewarming built into their controlled lamps on their pinball while nobody else saw it as necessary.

So in theory it would just make sense to disconnect the ground wires unless you wanted an instant pop of light? Disconnecting the circuit would increase flasher life wouldn't it?

maybe, maybe not. it would not always have current flowing, which could extend the life, but it also then has a much greater thermal shock everytime it turns on, decreasing its life.

What kind of led flashers did you use? Been thinking of doing this for a while. Maybe post a vid if you can.
Thanks

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.

Thanks. Did you do the 6 flashers that are all in a row at the top of the playfield? If so, are they too blinding because they point right at you? Oh and I was just looking for a quick gameplay vid of how the flashers look when they go off.

And in my machine, I did not. That way I did not have to remove warming resistors.

I do notice that system 11 flashers just blast your eyes into the back of your head when they go off though. It's pretty awesome although I can understand why they would do away with the pre-warming to save some money on components.

Sorry for my ignorance, but I need to do this to my Space Station, I just blew 3 89 flex flashers, can you post a pic of what you did to yours?
thank you man

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.

, Im certain the voltage is too high for the 12 volts, are there cointaker flashers that are compatible, or some other LED Flashers, that are compatible with the #1251?

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.

*kbliznick*, you are awesome. THANK YOU for mentioning that. My F-14 came with nearly all the "middle" resistors on these boards missing - I assumed previous owner tried to use LEDs and chopped them off. (Maybe that's the case, but he chopped off the wrong ones).

I was assuming larger meant the resistor had more resistance, so I was confused about why I'm still getting the warming voltage!

A few minutes before I realized this I chopped the 5Ω resistors from the only board that had them, thinking they were the 330Ω resistors, and I saw a behavior change; a few flashers were able to go from *on* (warming voltage) to brighter when doing flashers in coil test. After clipping those off they don't; now they're all stuck at warming voltage.

Time to solder the *correct* resistors back on and disconnect the grounds! (I have a full set of replacements at hand.)

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Then can get so hot they actual desolder themselves from the boards.

True. That's probably pretty likely. Although there were still legs in some of the holes.