I have two of the 'souped up' LOTR flipper coils installed.

A few days ago, the right flipper quit. The fuse was blown. I installed a new fuse and the flipper locked up.

Installed a IRL540 in place of the 20N10L

Turned it on and the right flipper fluttered. Pressed the flipper button a few times. Then it locked up.
I expect the new MOSFET blew too.

Is this a problem with the coil? Diode?
Looking for suggestions before digging in.
The EOS switch opens.

https://groups.google.com/forum/#!topic/rec.games.pinball/O3-z3GR-eeQ

Unfortunately, no solution is documented.

I checked continuity on the MOSFET before powering up. It all looked OK.

With J9 disconnected, both coils test at about 3 ohms.
Only way to check the diode is to remove it. Will do that tomorrow.

And this is of little help.

https://pinside.com/pinball/forum/topic/rct-shorted-q16-transistor

https://pinside.com/pinball/forum/topic/lotr-right-flipper-pain

http://www.pinballrevolution.com/threads/7-stern-lord-of-the-rings.1695/

Thanks for the helpful replies.

I ignored rule #32 in the pinball maintenance code book*: When a solenoid Q blows, always replace the diode on the coil. I put a screwdriver behind it and the wire came apart easily. Replaced the diode and the MOSFET, and it works fine.

The coils are the aftermarket LOTR coils. More powerful than the originals, hence the lower resistance.

The diodes must be in the right direction since it has played flawlessly for ~5 years with these coils - although that is a reasonable question to ask.

*No such list of rules exists, to my knowledge. But there should be one.....