I am hoping some smart person can help me with a board/flipper issue I am having with my Lord of the Rings machine:

- Very recently fully restored my LotR but the flippers are the same (however the playfield was stripped etc so maybe something moved around)
- Got everything back together and play tested 3-4 games with no problems
- Then the left flipper suddenly died
- 3A fuse was blown next to flipper and would blow again if reinstalled
- Removed the driver board and found that the IC Q15 was reading weird (all legs grounded)
- Couldn't find a direct replacement so I did my best and ordered one from Digikey
- Reinstalled it and had the same issue (blown fuse)
- Reinvestigated board and found that the Capacitor C248 was shorted to ground
- Ordered a new capacitor and replaced it
- Same thing happened
- Thought maybe I had ordered the wrong IC so I asked around and got new replacement ICs (IRF540)
- Replaced both ICs (right and left) and both capacitors
- Carefully measured both ICs and capacitors and there was no short after install
- Put it back in the game and both flippers blew their fuse.
- When I checked the capacitors both had shorted to ground again

So at this point I am sure that when I try to activate the flippers it somehow shorts the capacitor? I have checked the resistors and they both seem fine.

It is also kind of weird because the left flipper will not flip at all but the fuse will blow immediately. The right flipper will flip once, stick up and then blow the fuse.

Someone recommended I replace the driver chip U2 but I can't see how that signal to the IC would cause a short in the capacitor. I would have thought the signal was a low amp on or off. Someone else said to replace the bridge rectifier but there doesn't seem to be one involved in the circuit so that doesn't seem to help.

At this point I would probably send the board off but I am not 100% sure it is a board problem and not something on the playfield. Although since both flippers are now not working I suspect it is board related.

I am kind of at a loss of what to check next, I have attached the part information if it helps. The ICs of note are Q15/Q16.

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So just to be clear, you are saying the IRF540 is incorrect?

I have a 400v 1A diode, that will work correct? I couldn't find in the manual where it showed it listed it out.

Okay so I have the correct MOSFET on order from Digikey. It is a IRL540NPBF which I think is fine. I am guessing the PBF might be "lead-free"?

It will be here in two day but in the mean time I checked the diodes on the flippers. I put my multimeter on Diode check and for reference checked a loose diode and one installed on the playfield which I think is working correctly. In both cases I get 0v one way and .55v the other direction.

When I check the installed diodes on both flippers I get .002v in both directions. I am guessing that indicates a bad diode?

I changed the diode, capacitors and installed the new chip and that seems to have fixed it. Thank you very much, that was a frustrating one. I think the original fault was the diode (which maybe blew the cap) but I went straight to the board and never thought about the diode.