Message #83897

[pinball-collector]

This is from http://www.pinrepair.com/sys11/index1.htm#coils

Diagnosing a Blown Solenoid Fuse.
If any of the game's solenoid fuse(s) blow immediately at power-on, here's some things to check:

    * First check the pop bumpers and slingshots to see if their "activation" switches are stuck closed (the switches that the ball triggers to make the bumper work). Prior to Big Guns and pre-System 11B, these "special solenoids" are unlike other coils in the game in that if their activation switch is stuck closed, it will keep the coil turned on (or will "machine gun"), and the fuse will blow.
    * With the game off, use a DMM and check the ohm reading of each and every coil in the game. On two lug coils just put the meter leads on the coil's lugs (on three lug coils there is a "common" lug, measure the resistance between the common lug and the other two lugs). All coils should be 2.5 ohms or greater. If a coil is less than 2.5 ohms, the coil is bad and essentially a dead short, hence causing the solenoid fuse to blow.
    * If the flipper solenoid fuse is blown, this is most often a bad or mis-adjusted EOS (End of Stroke) switch. See the flipper section for help with that.
    * If a coil is less than 2.5 ohms, there is probably a reason this happened - the coil locked on, heated up, and melted the insulation off the coil's windings. This causes a short between the windings, and lowers the coil's overall resistance. Usually this most often due to a shorted driver transistor which keeps the coil energized while the game is powered on.
    * For all coils found with less than 2.5 ohms of resistance, disconnect the wire(s) from one of the coil's lugs. For a two lug coil, there is a power wire which is usually a thicker wire or often two thicker wires. This brings power to the coil and is connected to the coil lug with the banded side of the diode attached. The other coil lug has the return wire which goes to the CPU board. I remove the thinner return wire because it is easier, but removing either will disconnect the coil from the circuit.
    * Power the game on with a new solenoid fuse. Does the fuse still blow? If not, you have found the start of your problem (the bad coil - now you need to find out what made the coil bad!) If the fuse still blows, look for another bad coil or perhaps a short from the coil voltage to ground.


Thank you very much for that lmfo,,lm sure its a voltage problem,,will check that first, to make sure its ok,,,,