If this happens as soon as the machine is turned on then you have a short. You'll need to track down the transistor and repair it. Check the coil chart in your manual for the magnet transistor. Its on page 100 in the yellow section. Ring magnet is coil 6 so it is driven by transistor q6. Now you need to grab your digital multimeter and test the transistor. In the continuity test mode, touch one end to the top of the transistor. Other end to ground. If it beeps then there's a short in the circuit. To make sure it's only in the board, you could remove connectors j10 and j8 and test. If shorted then the transistor needs to be replaced. If not sure how to do any of this then time to call a repairman.

Depending on your situation, rottendog makes a decent replacement power board for your machine. You could buy it and pop it in. Then you could sell your broken board and reclaim some costs. That could be cheaper for you than a repairman. The board would be different if it's a lotr 2003 vs a lotr LE.

Your Transistor is bad/shorted and will have to be replaced location on driver board Q6.

http://pinside.com/pinball/forum/topic/lotr-ring-magnet-update

Oh yea. I suppose it's possible for the short to be in the wiring or magnet. So before you buy a board do the tests to verify its really the transistor at q6.

It's most certainly the Transistor...A lot of stress is put on that Transistor when holding the ball and
will give out.

I agree it probably is. But it could be outside the transistor. Remember that power is always given to the coils and the CPU shorts ground to enable them. If there's a short in the magnet, wiring, etc it will behave the same as if the transistor is shorted. For a guy that isn't that technical, he needs to test for these things before putting in a new board and risking that it blows right away again.

F20 has to be a 4mp slo blo,A 3 amp will not hold up for long and will short out the Transistor.Keep in mind if your going to place a new Rottendog driver board F20 will be marked to place a 3 amp fuse on the board.Make sure you put in a 4 amp slo blow instead of a 3 amp,If you place a 3 amp you will short that Transistor again,I already been through all of this with both Stern and Rottendog boards.

What is all this new board talk? It's one three legged transistor... find someone to replace this first, if it locks again, then look elsewhere, but as others have mentioned, there is a 95% chance this is the issue.

Do magnet coils act the same for common resistance checks on coils?

It sounds like we are past this point. I had the same problem on my TAF and it was a blown transistor. A friend with a slew of know how was very, very nice and came and fixed it - took about 20 minutes.

It's way beyond my skill level and I would have had to order a new board.

I offered to pay my friend for doing the repair. He just wanted the cost of parts... I think it was $2. Wow.

Its a common problem. Pinballife sells a heavier duty transistor for that application because its so common. Its their part number 22NE10L for $2.95.
If you own a LOTR you might want to throw one in on whatever your next order is just to keep it around. I bought two and used one, then had to give my spare to a friend who needed one. I put a 5 amp fuse in it after that too and have had no problems since.

I agree for those of us that can handle the task, it's not that difficult to replace a transistor. For those that can't, it's infinitely difficult. If you have to hire a professional repairman for this then it may be cheaper to instead buy a board, swap the board, and sell the old board. A board with only one blown transistor can still sell for a decent price. so suggesting a new board is not that ridiculous. Just laying out all the options.

Actually, far better (and cheaper, and faster) to find a friend with rudimentary soldering skills to replace the transistor. Or (*gasp*) spend a bit of time and learn how to solder and identify parts yourself. These are basic skills that you'd be well-advised to have if you're going to own and maintain things like pinball machines. It is not rocket science. Lots of info/help is available (like in this thread), along with photos or other detailed info on the net. Just do it step-by-step. Do you put in a new car engine when it fails to start? Pretty much the same thing....

FWIW, BOTH of my flipper drive transistors blew on my LOTR LE within the first 8-9 months of owning it. I replaced them with the beefier transistors; not a hint of a problem since. Cost me about $5 in parts, only had to wait a few days the first time. (I ordered a couple extra transistors just in case). Buying a new board, installing, hoping to sell the other (non-working) one, with payment and shipping hassles, swallowing the hefty loss. Does that sound like the best way to go? Not to me or any other pin owner I know!

You can check it yourself with a DMM. This is very easy.

If you're going to have pinball machines, you need to learn repairs anyway. Get a used board and practice removing and re-soldering. You need a temp controlled soldering station for board work. You likely find someone to do this for you, but for future issues, it's good to start the learning process now.

It just depends, but usually just replacing the transistor is enough. They're easy to replace and cheap. Buy a few, replace it, and see where you're at.

For me, I would take the board out, buy the transistor and then take it to a friend to fix the board and show me how to do it....might save some time and frustration....but eventually learning how to do this stuff is good if you are going to own multiple machines...

Solid advice! It all gets easier (and fun?) over time.