I couldn't come up with schematics for a World Cup of ipdb.org, but I believe we can still use the schematics from Hot Tip (another Williams system 3).

Following them, Q45 is for the coin door lockout coil. If you want to eliminate it from the equation, clip the wire going to lug of the coin door lockout coil that's on the non-banded side of the coil's diode. Screenshot_20230121-163705.png

F2 should be a 2.5a slow blow fuse. If you try replacing the fuse again, listen/watch for any coils that may be locking on as soon as you turn on the game. A shorted/bad transistor can cause a coil to fire and lock on until the fuse blows (typically very shortly after you turn the game on).

Make sure to get the correct fuse for F2 (and get extras for troubleshooting!) You should also check the remaining fuses in the game to make sure they are correct (proper amperage rating and slow/fast blow)..

Screenshot_20230121-163821.png

Check the pop bumper switches, make sure neither are gapped too closely. Also make sure the solder lugs on the switches aren't mashed together or shorted to anything adjacent etc. I believe they can cause the coil to lock on if they get stuck closed.

Solenoids 1-5 would appear to be all the other playfield coils beside the flippers and the pop bumpers (both of the pops are considered "Special Solenoids").Screenshot_20230121-222310.png

It's possible you blew another fuse at F2 when the coil started smoking before. If anything, you can disconnect the ground wire (the non-red wire) to any suspect coils to try to narrow down which is locking on/blowing the fuse.

We'll need to see the wiring to the coin door lockout coil. Any chance it's wired backwards? Diode shorted/bad or missing from coil?

Not sure why the other 2 would have fried though. Based on advice from Clay's repair guides, I typically replace the 2N4401 predriver along with any TIP122/102 that blow on those boards. Def worth taking some time to follow his troubleshooting guides, he covers many common scenarios: http://www.pinrepair.com/sys37/index1.htm

Red wire should have been on the *banded* side of the diode. That's why that transistor blew with such vigor. With those readings, I'd replace the diode on the coin lockout coil (or just leave the ground wire to it disconnected). You should only get a reading between 0.4-0.6 in one direction, nothing in the other.

Left pop bumper is a dead short with 0 ohms -- you'll need to replace that coil...the other one might still be ok though. Check for correct wiring with respect to the banded side of the diode!

Damn, I have to assume the lack of diodes should explain the problems with Q2+Q4. Weird! Guess you'll need a couple 1N4004 diodes as well (might want to grab a couple of those aforementioned 2N4401s as well)

It sounds like you should be headed in the right direction now. One last note: to test a diode, you often need to disconnect one leg from the device it's attached to in order to get accurate readings.

Be sure to post any further questions etc. Good luck, and keep us posted!

Both of the pop bumper coils need to have diodes on them--the schematic shows them here (these are considered "Special Solenoids"):

Screenshot_20230128-001101.png

Any chance the diodes are on the other side of the coils (the side facing the bottom of the playfield)? If the left pop coil has no diode installed, I'd have to assume that's what caused it to lock on when you turned on the game.

The purpose of the diodes is that they keep the current flowing in one direction--which is critical to many DC circuits, including this one. I'm not properly/traditionally educated in electricity, but in a nutshell: when the coil "fires" (momentarily activates) the electricity is flowing *in one direction* from the power source, through the coil, to ground. Once the power or path to ground is removed though, some of that current can travel backwards FAST--which in this case is leading back to the TIP122/102 transistors, their predrivers, and chips. The diode kinda acts like a check-valve--it only allows the current to move in one direction.

You saw how much force it can have when you saw the transistor blow for the coin door lockout coil. Note the presence of the diode on that coil. Wired up properly (**red wire on banded side of diode**), it shouldn't blow the transistor again. In some cases, the lack of a diode (or improper wiring to the diode) will blow just the TIP122/102 transistor but it's still capable in some cases of taking out the pre-driver and chips. I don't think I've seen too many cases where the chips got hit, and I wouldn't rush to replace the PIA just yet.

Honestly--I'm not sure why the right bumper *isn't* locking on. Perhaps the transistor on that side failed as well, but didn't create a short that could lock on the bumper? I'd investigate the drivers and predrivers on the driver board for both of those bumpers again.

It's possible the shop you bought the coil from doesn't include diodes on their coils, or you simply ordered a coil that doesn't include one installed. Some pinball manufacturers place the diodes elsewhere in the game, so the coils can be wired up either way--not the case with these Williams games though. Double check the resistance on both coils, add a diode to each, make sure red wire is on banded side of the coils.

You're probably gonna need to replace the transistors on the driver board for the pop bumpers again too. I'd definitely check them before turning the game on again. If they're out of spec compared to the working transistors nearby, I'd go ahead and replace them. I know what a pain in the ace it can be having to take the boards out and reinstall them over and over, so make sure to check everything carefully before giving it another shot. At this point I think you probably (hopefully!) have everything you need to get the game working--just need to take the last few steps to make it past the finish line.

Good luck!

Sounds like progress!

Is 2J13 connected? That's the connector for the pop bumper activation switches.

Regarding the chips that were replaced, make sure they were installed with proper orientation for pin 1 (I presume you already know this stuff, but it's never a bad idea to double check).

If all that checks out, you may have to recheck your work and make sure everything is good--no accidentally broken traces etc.

Hopefully you'll catch the culprit soon, I'm just not exactly sure where else to point you since you've covered nearly all the bases already...

Woo hoo!

Glad you got to the bottom of it. I knew you were getting close! Well done!