edit:
I was corrected. this is a known issue with some earlier games and bad magnet boards. I would contact stern (1.800.542.5377) or your local distributor about this

ps
are you running the latest firmware (1.70) on your machine? stern will probably ask which version you're running

Is this an original game or from a newer run? The original run had issues with the magnet board. The boards would develop a bad transistor that would then allow that resistor to heat up and fall off the board. Stern should replace the magnet board for you. Chaz and Pat @ Stern have been very helpful trying to sort out the issue. I have an early original run premium. I have gone through several magnet boards with this issue. At this time I seem to have gotten one that works. It will still however sometimes just randomly blow the magnet fuse. Doesn't happen very often...just every once in awhile.

Phoebe

https://pinside.com/pinball/forum/topic/magnet-board-old-and-new-w-pics-metallica-le

Here is a link to the thread, and there is also discussion about it in the MET owners thread, but it might take awhile to find it (that thread is pretty long!)

Phoebe

There's some issues with the magnet board that Stern has not figured out. I've had two different games with the new magnet board blow fuses. I've probably spoken to Chaz half a dozen times and I've never gotten an answer. I've basically given up. The games I'm going to describe are on location, so the issues we are seeing are with the game powered on for multiple hours during the day. You may not see issues if your game is at home and played then turned off.

The first game kept blowing the fuse, this was with the revised board. After multiple calls the owner bought a new board as it was out of warranty. The new board worked fine but also blew the fuse after a few days. Basically the same issue as the first one. The owner got tired of the issues and eventually sold the game.

The second game had the old version of the magnet board. It never blew the fuse in over two years of continuous use on location. Not once. The only problem was occasional false hits. I finally called Stern and had a new board shipped to me to replace the old version (this was covered as a warranty replacement). The new board stopped the false hits, but the next day the fuse was blown. So, the old board never blew a fuse in over two years but the new board blows the fuse in a day? Something isn't right here. I put the old board back in the game and it has run for a couple months and never blown the fuse again. I'd rather have occasional false hammer strikes than a blown fuse every day.

I called Stern again and described my experience with both of these games. They were no help. So I've resigned myself to running the old board and deal with the false hits.

I just called Stern on this issue. I had a replacement board about 6 weeks old that blew Fuse F7. Pat at Stern told me they are sending a new board.

Magnet coil is supposed to be in the 3-4ohm range.

Did anyone figure out what the deal is with the new magnet boards failing? I'm on the second replacement now (third board counting the one it shipped with). It only seems to last about two months before the fuses blow. Also, the replacement boards make a high pitched sound when the magnet sensor is triggered. Super-high-pitched, like a bad arcade tube monitor "singing".

My MetLE magnet board failed today.
It is new version, replacing the original (defective version) by distributor when game was new.
https://pinside.com/pinball/forum/topic/magnet-board-old-and-new-w-pics-metallica-le

Game has been flawless until today when a puff of smoke and bad smell emanated from playfield

Coincidentally I only installed new Stern carbon balls from my Maiden LE, I was previously running ninjas until they became magnetized.
This game is very low play with only 140 games in last 5 years.

The 15P10PL Mosfet has shorted out causing the 5W ceramic resistor to cook.

Question ? Can I just replace Mosfet ?

Anyone else been down this path ?

Thanks

20190914_170740 (resized).jpg

Did you check the resistance at the coil to make sure it didn't short out and take out the board?

Yeah all good thanks Vic, All 3 mag coils are at 5-6 ohms

Probably a one-time mosfet event, then.

BUT, IF it happens more, then have a look at your SAM board. Stern replaced 3 or 4 magnet boards and a few coils under warranty because the boards kept blowing within about 3 months on route before Stern decided the problem might be the SAM driver board. Changed that out and never had another problem again. It was a weird one.

Thanks for the heads up

Does this actually happen? ... a coil is nothing more than a solid wire wrapped X number of times around a spool; without the entire coil melting into a blob of copper, it's actually physically impossible for the inner coil winding to contact the outer winding.

That being said ... the magnet board is designed in such a way that the resistor will draw close to 8 watts of power if the mangnet windings are open or the connection between the magnet board and magnet is broken. The original REV A magnet board had a 10W magnet board resistor that wouldn't burn under these circumstances but for some reason Stern changed this (I assume for cost) to a 5W resistor; however, the original 10W connection is still in place as well as the 10W resistor silk screen on the top side.

How do I know all this?

This happened to me as well.

DSC00317b (resized).jpg

My replacement board from Stern now has the appropriate 10W resistor installed as I modified this before installing the board. Please note that this resistor is also elevated off the board so that in the rare event it burns, it cannot take the board with it.

DSC00690 (resized).JPG

I've definitely had coils short out in the middle and take out transistors, so it happens for sure.

Yeah, that is really weird, So it appears the SAM board only drives the Sparky and Graveyard magnets.
The separate driver board under the PF is for Hammer lock magnet only.
I re-checked impedance of all Mag coils and they measured the same about 5 ohms.

I have replaced Mosfet and upsized resistor,

This has got coffin lock working perfect again Such a cool mech

Thanks for all the feedback everyone.

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20190916_202604 (resized).jpg

20190916_194926 (resized).jpg

I think that's because the magnet for the coffin lock senses resistance change when the ball goes over the magnet post to know when to grab the ball, and the sparky and graveyard don't. That logic is what goes back to the SAM board and may be why replacing the SAM board fixed our magnet board issues when replacing one board after another and the magnet didn't.

If anyone could tell me where to source the resistor 10W 160R J and the Mosfet 15P10PL, I'd really appreciate it. My web searches have turned up nothing....

Thanks in Advance

Mouser has the mosfet:
https://www.mouser.com/ProductDetail/Infineon-Technologies/SPP15P10PL-H?qs=sGAEpiMZZMshyDBzk1%2FWi5ISJmYFIFJTSWc4jjkDnbo%3D

I'm sure they have the resistor or a sub, too.

They do:

https://www.mouser.com/ProductDetail/603-SQP10AJB-160R

I'm glad you mentioned this as I just lost another board, this one is an odd failure though as all I have to do is power cycle the machine and it starts working again, but fails after a couple of locks. I'm starting to suspect that there is an issue with either the +5V power or the communications with the driver board. I may have to swap in my driver from Star trek and see if it fixes it.

Thank you both very much!

Even with my less than perfect soldering skills Metallica is now back up and running - thanks for the help!