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What's happening to my minipac??
supafraud:
Hi guys, so for those not aware I've created a software engine for a EM pinball machine. Unfortunately I'm stuck with a strange problem. The way that I have the targets and such hooked up to my software is with a minipac that is wired to the various drop targets, roll over targets etc. This works great until I start firing off solenoids. After a few solenoids fire off, for example if I just hit the flippers a few times, the minipac "disconnects" and is not detected and stops giving me input. Sometimes if I wait a few moments windows detects it again. At first I thought it was a wiring problem so I rewired the entire playfield (not awesome) only to have the same problem. It's not the driverboard because I have the same problem when it is dissconected and I am just hitting the flippers which are hardwired to a seperate power supply. In fact everything at this point is totally seperate from the computer with the minipac on it and the minipac itself. It's not vibration from the solenoids because i have moved it from having any contact with the playfield. I'm not sure how but I think it's some kind of electro magnetic thing going on. Does anyone have any ideas because this is driving me nuts! All I can think of is trying to shield the minipac with something but I think it's possible that the wiring harness would have to be shielded too. Please let me know if you have any ideas, the flippers are running 50volts AC from the original 1975 Bally transformer. The transformer itself is at least 3 feet away from the minipac and the closest solenoid is about 2-3 feet away currently. Obviously the wiring harness is only a few inches from the various solenoids but nothing is touching. So confused.
:banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead:
BobA:
You might be inducing spikes into the ipac input wiring by having some of the wires running close to each other. Can you separate all the ipac input wires from the selenoid wiring? Can you use a diode across the flipper coils to damp the spike they create when the field collapses? A 1n4004 diode placed across the coil of the flipper in reverse will damp the spikes.
WindDrake:
--- Quote from: BobA on January 10, 2013, 07:04:39 pm ---You might be inducing spikes into the ipac input wiring by having some of the wires running close to each other. Can you separate all the ipac input wires from the selenoid wiring? Can you use a diode across the flipper coils to damp the spike they create when the field collapses? A 1n4004 diode placed across the coil of the flipper in reverse will damp the spikes.
--- End quote ---
Bob beat me to it. I'd bet the solenoids are making the Minipac go into overvoltage shutdown from the Back-EMF out of the Solenoids. Diodes or Optoisolation will fix ya' up.
supafraud:
thanks fr the replies. I actually happen to have a few 1n4004 diodes that were soldered to some switches i ordered. These little guys can handle to 50v 10 amps? also on the flippers there is the hold coil and the firing coil, how would that get hooked up?2 diodes?
BobA:
I think the best way is 2 diodes as there are 2 coils making spikes on each flipper.
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