(Topic ID: 307307)

Monday Night Football - F2 fuse blows on startup

By DrCarbon

1 year ago

Topic Stats

  • 2 posts
  • 2 Pinsiders participating
  • Latest reply 1 year ago by wayout440
  • No one calls this topic a favorite


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    #1 1 year ago

    Symptoms - VUK, slingshots, and pop bumpers do not work. Coils have been replaced.

    Details - On the Power Supply Board (Rottendog replacement), the only unlit diagnostic LED says it's the 28VDC output. On startup, the 2.5 amp slo-blow fuse blows (F2). Foolishly/bravely, I systematically replaced the fuse with stronger ones (3, 4, 6, then 8 amp). Only the 8 amp fuse held, and everything started came to life... until the coil sleeves started melting about 30 seconds later. The board seems to have survived the experiment.

    Any ideas on why too much power is being supplied? Any suggestions on actions to take?

    Many thanks in advance.

    #2 1 year ago

    First a little theory, it is a question of how much power, but too long. All those coils expect a brief momentary pulse (the transistor driver circuit is a switch that makes a connection to ground). It's likely something in the CPU logic is "telling" the driving transistor to stay on when the power is supplied.


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