Once every three or four games (or so), F2 is blowing on my High Speed. Every single time it has happened, it has been at the moment of pressing the right flipper button.

This has only become a problem recently, and might coincide with replacing the flipper button double leaf switch on the right side.

Any suggestions?

Thanks, didn't even realize improperly gapped switches would cause that. I know it's an 1/8th of an inch for EOS...is it the same for the flipper button switches?

I widened the gaps a bit on the flipper button switch, and I bent the switch lugs away from each other on the EOS switches on both right flippers. Just played for 45 minutes and the fuse never blew.

Huzzah (for now)! Thanks all.

...and...not actually fixed. Blew on my first game tonight.

I'm not in front of the machine right now, but it's the lowest of the four fuses on the power supply (it's offset a bit to the right of the others). I think it's actually for all solenoids. When it's blown, you don't get anything: no flippers, ball doesn't launch into the shooter lane, etc.

Manual simply says: 2.5A, 250v, S-B...though I have a vague notion that there is a card inside the backbox that gives a little more info.

After widening the gaps on the flipper switch so that I could more easily flip just the lower flipper without triggering the upper one, I noticed that the fuse blowing was only happening on really hard button presses. So I investigated the upper flipper.

Turns out, the coil diode had a bad solder joint on one side. Touched that up - no more problems! (Granted I only played 10 games, but that's by far the longest it has lasted in quite some time)

This is actually still an ongoing issue for me. (It's the fuse on the power supply board we're talking about).

I thought maybe I had it wired incorrectly and found a pic here: https://pinside.com/pinball/forum/topic/new-guy-i-need-help-with-williams-high-speed-flipper-coil-wiring that shows that I did have it wired wrong. I still have the issue after rewiring to look like the one in the photo.

Will start going through the things mentioned by wayout. (The diode on the upper right is new).

Also when people say "check the eos"...mine its closed at rest, and opens when the flipper is extended. What would be wrong about the EOS that would cause a fuse to blow?

It's definitely the "other solenoids" fuse, on the main power supply board. When it blows, most solenoids no longer work...you can't even launch a ball because the trough won't feed them into the shooter lane.

I'm fixated on the flippers here because this fuse blows when the right flipper button is pressed (not every time...and I think the lower right flipper might be fine but it's the upper that causes it...again, sometimes).

Here's what I've done since: re-soldered the wires to the right flipper button switches (trying to put it back a little more cleanly than it previously was), checked the caps (which were good), and adjusted the upper right flipper EOS to be just a smidge wider when open.

Then I played about 10 games, trying desperately not to use the upper right flipper (pushing the button in only enough to activate the lower flipper, though I'd hit it hard enough to activate both about one in 10 or 20 flips) and had no problems.

Then I went full throttle and played for about 30 minutes, using the upper flipper whenever it was called for. No issues. So...maybe it was the wiring to the right flipper button switches?

Those are good suggestions wayout - I really appreciate the help. Not 100% sure this is resolved yet, but the last 30 minutes was a good sign.

I think the reason it seemed like the flippers weren't working after blowing the fuse is that you couldn't start a game, so it wouldn't let you flip.

Still having trouble with this. So, the upper right EOS doesn't activate in the switch tests. Even if I open it manually (not by flipping). Shouldn't it? I thought perhaps there was a bad connection, but there is continuity to the coil lugs when closed, and not when open. And I just replaced it with a brand new coil. Same thing...opening the switch manually doesn't trigger anything in the switch test.

I'm stumped.

Thanks for the help, much appreciated. What would be the best way to test if/where it's grounding out?

I have it wired just like in the pic here: https://pinside.com/pinball/forum/topic/new-guy-i-need-help-with-williams-high-speed-flipper-coil-wiring#post-122671

Redacted. Just now seeing your previous posts.

Just wanted to follow up with this in case anyone else stumbles across it.

I put a little hat (of sorts) on the part of right flipper leaf switch that controls the upper right flipper (to disable the flipper). The fuse did blow while playing, so now I knew it was the lower right flipper. Not sure why I had been fixated on the upper right all along - but perhaps because it always seemed to happen while hitting hard to make the ramp shot.

I then started messing with both right EOS switches, wondering maybe they weren't opening enough at full extension of the flipper. My very next game, the upper right flipper was weak, really weak, and then it started getting stronger with each flip, until finally the fuse blew (and it happened pretty quick, maybe in 20 flips total...which was much quicker than normal). I look at it again, the EOS was not closed at rest (and it should have been, this is a normally closed switch).

So...now I realize that the problem all along has been EOS switches not closed when at rest. I adjusted both right side EOS to ensure they are tightly closed at rest, and no more problems.

Though it was frustrating to spend weeks troubleshooting something that turned out to be a tool-less 20 second fix, it was a good lesson to learn. I just wasn't aware that an open EOS could cause this. And, the fuse that was blowing isn't the one I would have expected, given that it seemed to be a flipper issue.

The lesson came in handy when after finally getting the right side working, I almost immediately blew the same fuse flipping the left flipper (it had never happened from that before). I changed out the old pitted, charred EOS, made sure it was adjusted correctly, and back to playing in no time.

Thanks all!

Okay, so this actually still isn't fixed. I'm going to go investigate right now.

Things I've done recently:

- Replaced the upper right coil. Still had issues.
- Moved the old upper right coil to the lower right flipper. I did this because it wasn't going to be easy to test the diode on the lower right coil, and I knew the one on the old upper right was good. Still had issues.
- Replaced the (brand new 1 month ago EOS) on the lower right flipper. This EOS had become a bit charred, and looked like it might not have always been making contact when at rest (even when I tried to push it back together). Still having issues.

Does it mean something that this EOS became a bit charred, after only being in for a few dozen games? Other than perhaps it was not gapped correctly?

One other thing that seems to be happening more frequently now - I'll get a "warning". Hit the right flipper button while playing and the flippers die, ball drains, and I hear the beep - that sound it makes when the game has all the balls in the trough and is ready. Then I can start a new game, and the fuse will eventually blow in the next few games.

I've never had the "warning" happen more than once. It's always closely followed by the fuse blowing.

The resistance on all three coils seems consistent with one another (remember, one of them is brand new). The one thing I haven't done yet is tested the coil windings. How do I do that specifically?

One other thing I tried - I bent #38 (the lower right engine revving EOS) in such a way that it would always stay open). Still blew the fuse.

And now I'm out of fuses.

Yes, it's the other solenoids fuse (the 2.5A SB). It has always been that same fuse. And yes, I do mean the power up confirmation tone/beep.

Thanks for still helping me on this.

Unfortunately this is still an issue - but it's so infrequent that I've just been replacing the fuse every few weeks instead of trying to resolve it. I'm interested in figuring it out though, so hopefully I'll have an update eventually.

Here is the latest on this...

Talked to the local repair pro, who immediately asked if I had the capacitor on the EOS. I didn't. I had actually done a rebuild with new EOS switches, but did not put the capacitors on because, hey, they weren't there previously and it was working fine.

When asked why a non flipper fuse would blow because of that, he said that one of the other fuse values was probably wrong.

So...I discovered that the one single fuse (the one in the lower right of the backbox, not mounted on any board with "2.5a slow-blow" label) was a 5A fast blow. I added a capacitor to the EOS, changed the fuse to the correct value, and have played a few games with no issues.

However, the problem was so intermittent, that I can't say for sure this is fixed. I need to put capacitors on the other two EOS switches, and then play for a few hours and see what happens.

I really have no idea if this accomplished anything yet.

Just wanted to give a little update and ask for a clarification.

The main flippers each have two leaf switches. The first one that gets triggered is closed at rest, and the second one is open at rest.

I nearly rolled the score a week or two ago, and got to enter my initials for the first time in a long time. The right flipper button wouldn't cycle through the letters, but the left would.

So, I went into test mode to check that out, and discovered that the left EOS was triggering when flipping, but the right was not. I looked at it, and visually, the first switch is opening, and the second switch *looks* like it is closing, but it actually wasn't. I adjusted it, and now it closes. (And re-reading my posts above, I can see that I may have adjusted it to not close intentionally).

It's that second switch that triggers the EOS switch message in switch test. Is that correct? Looking at the matrix it doesn't seem like both switches are listed there.

TL;DR Which switch is *actually* the EOS switch, and which one is for the revving? And which of those two should trigger the message in switch test?

Cool, thanks for your help wayout.

One of the right side flipper coils had one of its wires (to a lug) stretched tightly and passing across one of the other lugs. Adjusting that so it wasn't touching the other lug anymore was the last thing I did (a few weeks ago) and I haven't had any issues since then.

Hoping it's fixed, but I've done so many small things and it happened so infrequently, that I don't think I'm going to be quite sure what the actual fix was.