Star Trek (LE)
Stern, 2013
Star Trek (Premium)
Stern, 2013You're currently viewing posts by Pinsider G-P-E.
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Quoted from newpinbin:Ok it was the Q12. Part is in ST is back!!!!!!!!! 100% Thanks for your help. My friend did the re solder for me.
OK --- that's progress but you're not quite completely out of the woods yet. Check the back-EMF diode (tied from coil to +50V). If it's bad (open) - Q12 will fail again.
Yep, whenever there are controlled coils then there has to be back EMF diodes. They are shown in the drawing in post #3 above.
He mentioned the blown transistor. *Something* took out the transistor and there is a good chance that a bad diode can do that.
When you hold a ball with the flipper on this particular machine, it is pulsing the coil to hold it. This is turning on and off the transistor in rapid succession causing a no-stop stream of back-EMF pulses.
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Omaha, NE