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Someone help me understand this.
I don't think it's the solenoids, as I've tested several out of circuit, old and new.
Why would a diode test across the solenoids - across the two spades - reflect positive values with test leads being swapped on a DMM in diode test mode?
I assume there's something to do with the coil winding, but not really finding anything to help solidify my understanding.
TIA!
Quoted from Quench:Diode test on your multi-meter tells you how much voltage it takes for a diode to conduct, typically around 0.6 volts in one direction only.
A coil winding's low resistance is like a short circuit, your meter is telling you the coil is conducting when it applies at 0.02 volts (negligible) across it and it will conduct both ways.
For this reason you can't test a diode in circuit on a coil. You ned to disconnect one diode leg.
To measure the coil you need to do it in resistance mode on your multi-meter. There's guides out there that can tell you the DC resistance expected for different coils. Some of Marcos coil wrappers list the DC resistances - below is a Bally flipper coil:
3.1 ohms for the primary thrust winding
322 ohms for the secondary hold winding
[quoted image]
Quench - ok thank you very much, but another question - I am able to measure diodes properly on other coils, the three lug coils, wouldn't those coils (inner and outer windings as I understand them) also short the diode out?
TIA.
Quoted from Quench:Can you give me a coil model for example?
Do you mean the Bally 3 lug coils used in solenoid expanded games?
Maybe - for some reason, maybe it's oldtimers, the theory wasn't 'clicking' with me. The diode attached to a two lug coil is part of a closed circuit, so that would explain (I see it now) that the diode would not read once on that coil unless disconnected from the circuit.
I can visualize and pull up references to how a coil works - simplest being a wire wound about a nail, connected on each side to a battery.
I just wasn't getting it the day I posted that. Heck, I even mounted a coil upside down in a bracket and couldn't figure out why I was blowing a fuse.
Sheesh. Some days I should just go to bed early.
Is there something different about the 3 lug coils in solenoid expanded games?
TIA
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Anchorage, AK