(Topic ID: 238051)

ToM: dead trough coil?


By Brijam

8 months ago



Topic Stats

  • 6 posts
  • 4 Pinsiders participating
  • Latest reply 5 months ago by Brijam
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#1 8 months ago

I couldn't get the trough coil to fire on my Theatre of Magic. Swapping in a different driver board didn't fix the issue. The coil looked okay but I ohm'ed it and it read zero, so I'm guessing that's a toasted coil, or more likely a broken wire on the coil? It's an AE-26-1500 and there aren't diodes on it.

Question before I swap that coil out, are there upstream issues I should look at so I don't just cook another coil?

#2 8 months ago

I'd take a pin or something and dig around the thin wires from the coil to the coil lug. If one is cracked or broke, solder it.

LTG : )

#3 8 months ago

A coil is wound wire that will read very low ohms. Pretty hard to tell a bad coil from an ohm meter reading unless it reads open. If the coil is actually shorted, which is doubtful unless it's melted, most the time the drive transistor is also bad.
Go into solenoid test, select this solenoid, then check the volts. During test should read 50-75vdc on one lug of the coil all the time, and the other lug drops low as the game attempts to fire the coil.

1 week later
#4 7 months ago
Quoted from Ronkz650:

A coil is wound wire that will read very low ohms. Pretty hard to tell a bad coil from an ohm meter reading unless it reads open. If the coil is actually shorted, which is doubtful unless it's melted, most the time the drive transistor is also bad.
Go into solenoid test, select this solenoid, then check the volts. During test should read 50-75vdc on one lug of the coil all the time, and the other lug drops low as the game attempts to fire the coil.

All of the solenoids are reading more like 25vdc. I didn't close the coin door or hold the switches down.

#5 7 months ago
Quoted from Brijam:

All of the solenoids are reading more like 25vdc. I didn't close the coin door or hold the switches down.

Coils normally will not operate from the diagnostic menu if the coin door is open or if the plunger to detect the door being closed is not pulled out.

2 months later
#6 5 months ago

Swapping for a new coil fixed the issue.

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