Tech: Twister Blowing F20 Fuse

Fatsquatch

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Alright, here's how it goes every time:

The game plays perfectly -- including the skill shot and diverter -- until multiball starts. When multiball begins, you can hear/feel the disc magnet firing up, and as the balls drop onto the disc, they're held in place. However, the disc doesn't begin to spin as it should, and the balls just sit there on the disc. (The disc spins normally all throughout the rest of the game.) As expected, the disc eventually releases the balls and the game continues as it should. However, the magnet features will no longer work, as the F20 fuse will be blown.

NOTE: The magnet board is brand new and came with the recommended diode update. The other magnet-related updates suggested by Stern have been done to the machine. The game is running on the latest (brand new) ROMs.

I've repeatedly looked over the wiring and can find no problem areas that may be causing a short. I'm quite stuck...

Any ideas?
 
What size fuse are you running?

My LAH kept blowing a fuse in the head *instead of the 3 fuses on the playfield for the magnets*. I rebuilt the magnet board, put it back in, and good to go now...

Just because a board is new doesn't mean it can't have issues.
 
3A 250V -- as indicated by the manual.

That would massively suck if it were the new board, but you're right...it's entirely possible. (And seems fairly likely when I think about how that fuse blows every time the magna-disc is engaged for multiball.)

I wonder if I should just go ahead and request an exchange from Marco?
 
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Also: Replace the fuse and check the magnet in test. Mine was blowing the fuse in test mode also, but don't leave it on for too long.

Thought: Magnets can go bad also, but I don't remember how to test them to see if they're good or not.
 
Also: Replace the fuse and check the magnet in test. Mine was blowing the fuse in test mode also, but don't leave it on for too long.

Thought: Magnets can go bad also, but I don't remember how to test them to see if they're good or not.

I'll definitely try that as soon as I pick up some more fuses. Thanks!
 
Under "Diagnostics > Twister Specific"' I ran both tests:

- Disc Magnet Test
- Diverter Magnet Test

On the former, the disc spun while the magnet engaged and held the ball. On the latter, the magnet engaged and held the ball as well. No fuse blew.

Started a game and everything was fine (skill shot worked with the disc grabbing/holding/spinning the ball, and diverter grabbing/holding ball), but on multiball after the third and final ball was held by the disc, the disc never started spinning. After a few seconds the three balls were released by the disc, but the magnet features no longer worked as the F20 fuse had blown as expected.

This is quite confusing and irritating...
 
Sounds like a board issue to me, but can't say for sure... Hopefully someone will chime in with more knowledge on the subject.

It works fine with one ball you say. Try the test with two balls and if that's fine then go three. My thinking: Maybe with three balls the magnet is having to put more power than it can handle which is causing the fuse to blow or something?

Somewhere in one of the guides it talkes about checking the magnet *I think it's resistance* with an ohm meter to determine if it's good because they can go back and cause issues.
 
Thought I had it figured out...

While I had been checking the continuity of the fuse for the disc magnet under the playfield, I hadn't noticed that it was a 250v 5a fuse, instead of the 250v 3a that it's supposed to be. I replaced it with the correct 3a fuse, started a game, and when multiball started, all 3 balls were held by the disc and it started spinning as it's supposed to. "Victory!", I thought, so I turned the game off, checked all fuses for continuity (they were good), and put the glass back on.

Thinking I'd FINALLY enjoy a proper game, I turned the machine back on and started a game. All was well till multiball, when it went back to its old tricks of holding the balls and not spinning the disc -- blowing a fuse in the process. Only this time, it was the fuse for the disc magnet under the playfield; the F20 fuse in the backbox was fine.

So, I replaced the fuse under the playfield, started another game, and yep...same ol' problem. Except for this time, the fuse under the playfield was fine, but the F20 fuse in the backbox blew.
 
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The manual, and the sticker by the fuse under the playfield, specify a 250V 3A fuse. The same goes for the F20 fuse in the backbox.

On the last 3 attempts...

  1. The game functioned perfectly till I shut it down after the first multiball mode had finished. No fuses blew.
  2. Started game; disc magnet fuse under playfield blew on first multiball. (I replaced fuse.)
  3. Started game; F20 fuse in backbox blew on first multiball.
/facepalm
 
I should probably go ahead and pursue a board exchange with Marco.

Thanks for all of your help, Spanks!
 
Although Marco's customer service rep was nice and apologetic, she told me they won't accept a return or exchange if the board has been powered up.

It was then suggested that I put the board on eBay to recoup my money.

After a little back-and-forth, I was ultimately told that they get those boards from Stern and have to pay a lot for them (making very little money in the process). I was then instructed to call 1-800-KICKERS for any type of support.
 
I have rebuilt a few of these boards including my own and they have always been rock solid afterwards. I don't have time to look at the manual right now, but what else have you done? Have you replaced the connectors to the control board? Have you verified that there are no shorts creating an over current condition?
 
Ya know, I'm kinda miffed about Marco just flat out denying me an exchange, and pretty much telling me "Tough titties; we won't help you. Sell it on eBay".

Before I gave them damn-near $250 for that board, I consulted their return/exchange policy, taking note of the following, and feeling that things would be okay if there were a problem:

Exception: Electronic Assemblies & Components. Due to the delicate nature of electronic circuit boards and semiconductors, these items will be guaranteed for 30 days by exchange only. Any warranty items supported by the product manufacturer after 30 days will be provided directly by the item manufacturer.

I've had the board less than a week.

Buyer beware, I guess.
 
Ya know, I'm kinda miffed about Marco just flat out denying me an exchange, and pretty much telling me "Tough titties; we won't help you. Sell it on eBay".

Before I gave them damn-near $250 for that board, I consulted their return/exchange policy, taking note of the following, and feeling that things would be okay if there were a problem:

Exception: Electronic Assemblies & Components. Due to the delicate nature of electronic circuit boards and semiconductors, these items will be guaranteed for 30 days by exchange only. Any warranty items supported by the product manufacturer after 30 days will be provided directly by the item manufacturer.

I've had the board less than a week.

Buyer beware, I guess.


It is standard industry practice to not accept returns on electronics that have been installed. For all they know poor installation by you, or something else in your system, caused the problem and now you want to return a damaged board for a full refund...
 
I didn't ask for a refund of money, I asked for an exchange of the exact same part. If it's their policy to not allow exchanges of any such parts, then they should make that clear on their website, instead of saying that "such items will be guaranteed for 30 days by exchange only".

I don't see how my request was unreasonable in any way, as I was just following what they detail on their Return/Exchange Policy page.
 
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