(Topic ID: 252525)

Early system 11 coil issue

By monkfe

4 months ago

Topic Stats

  • 2 posts
  • 1 Pinsider participating
  • Latest reply 4 months ago by monkfe
  • No one calls this topic a favorite


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#1 4 months ago

so I recently got my high speed up after a full tear down. Despite my attention to watching the coil power/diode connection, I managed to still hook one up backward, and blowing a tip122(and f2). I replaced it and while doing so checked out all the drive transistors both pre drive and power for the solenoid drives. When i got to Q32 it seemed a bit off and I replaced it, while doing so I checked the predriver-Q28 which was giving me a DMM reading of ~232 both ways...figuring it was shot I removed it. When I bench tested it it seemed fine giving me a ~443 and blocking it in reverse? since I had not tested the coil yet (eject hole) I reinstalled everything and regained all but this coil (of course). So I removed the board and still have the same readings...so now I'm thinking I may have done some damage to the resistor networks, but before I start getting into that... I'd figure I pick some brains here as to what may be causing this anomaly. I wish I had just replaced the pre-drive as I had it out....but it seems fine? Thanks gents

1 week later
#2 4 months ago

...for those searching millennia from now...it was the nand gate keeping the pre drive high.

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