So the right flipper on my LOTR died last night. I checked the fuse and it was fine, so I'm thinking my transistor went. Which I've read is common with Stern games.

How do I go about testing the transistor with my DMM?

Cool. Thanks for the info.

Does Radioshack carry the IRL540N (I couldn't find it list in there stock) or do I have to order online?

Does the transistor have to be off board to test, or can it be tested on the board? I thought I remembered reading somewhere that it had to be off board.

Thanks. Will test tonight when I get home.

Did a test on both Q15 and Q16.

On Q15 with one lead on center I get a reading of .489 off of only one outside lead the other reads nothing.

On Q16 with one lead on center I get a reading of .014 off both outside leads.

Before testing I checked the right flipper fuse again and put a new fuse in which promptly blew before even one flip could be completed.

It doesn't even energize it just blows on power up or game start.

Will check the diode on the coil also, just to be sure. Then I'll order a few of the IRL540s, going to need more fuses as well since I'm down to my last 3amp 250V slow blow.

Thanks for the help, will report back after replacing the transistors. Though I am nervous about doing circuit board soldering, I've mainly only done coil soldering, etc. on EMs.

How do I check the resistance on the coil?

Got a .01 reading on both the right and left flipper coil. Tried the same test on my Williams games flipper coils and got a .14 reading on both coils.

LOTR

Yep, the coils use diodes. Strange that the LE does not.

Just ordered the more robust IRL540s since that seems to be the problem. Might see if a friend can do the solder work as he's more experience at board repair then I am.

Help.

Ok, finally got around to replacing the Q16 right flipper transistor and successfully installed the IRL540 transistor (New baby takes away a lot of repair time). Tested the new transistor before putting board back in the machine. With one lead on the center I got a reading of .489 on one outside lead and nothing on the other lead. This matches the reading a receive off the working Q15 transistor.

I then put the board back in the machine, put a new flipper fuse in, power up the machine and crossed my fingers. Sadly the right flipper fuse blows without so much as a flip. I then test the Q-16 transistor which now reads .379 on one outside lead and .379 on the other lead. So it looks like whatever the problem is, it has now blown the new transistor. Which is now reading incorrectly

I've tested the diode (multimeter set on continuity) on both flippers and get the same reading so that seems good.

Any ideas?

Morning bump.

Thanks for the tips. Will try removing the flipper coil and see if the fuse still blows.

Hopefully will get to it tonite after family bbq

When desoldering one of the coil lugs does it matter which?

Yes. My initial tests were on the transistor which looked to be bad (and seems to happen often with Stern games). Replaced said transistor and same problem of flipper not working and blowing flipper fuse continued to happen.

Finally have the time to desolder the flipper coil and test tonight.

I set the multimeter to 200 ohm and I get the following readings:

L flipper coil soldered - 5.0
R flipper coil soldered - 3.3

L flipper coil unsoldered - untested (didn't want to unsolder if not necessary)
R flipper coil unsoldered - 1.5

If I cut the diode on the left flipper will this determine if it's the coil or the diode?

Replaced the fuse and booted game with the right flipper coil unsoldered. The fuse did not blow, so it looks like it's the coil.

Since I already replaced the transistor before testing the coil, I hope that I didn't mess up the new transistor.

Thanks, will pull the board tomorrow and test the transistor again to see if it's been open/shorted. Going to order a new coil in the meanwhile from Pinball life.

Pulled board out (just easier to test that way) and got the following reading on the flipper transistors with multimeter set on diode:

Q-15 (working flipper) - lead on center and outside leg- .553, lead on center and other outside leg- 0

Q-16 (non-working flipper) - lead on center and outside leg- .295, lead on center and other outside leg- .301

When I originally installed the new transistor in Q-16 (before putting board back in an powering up) I had the following reading:

Q-16 (non-working flipper) - lead on center and outside leg- .489, lead on center and other outside leg- 0

The transistor readings where with the board out of the machine. Does that make a difference?

Yeah, I bought a few when I ordered just in case. Looks like it's just in case.

Putting in new transistor, just waiting for new coil to arrive (hopefully by Sat.). Hopefully this will work. I'll report back once complete.

Success! Installed the new flipper coil and another new transistor and she works!

Tested the diode on the old coil and got continuity both ways so it looks like it might just have been the diode. Oh well, just happy the machine is up and running again.

Thanks to all for the help!

LOL. Still haven't gotten to Valinor yet.

Yep, clipped it off when testing.