Was playing my TSPP tonight. Had a ball go into the Itchy & Scratchy saucer and not get ejected. Could hear a noise like it was trying to eject a few times, but the DMD then displayed a message indicating an error with the I&S eject coil. I then almost immediately began to smell a burnt electrical smell.

Shut things down and opened it up, but couldn't find any obvious smoking crater, so I powered it back on and ran through some of the diagnostics.

The simple Diag->Tech showed no errors despite previously noting that the I&S ecject coil wasn't working.

I went into the coil test section and found that none of coils #1-#11 would fire other than the one controlling Homer's head.
List of them here.
http://mirror2.ipdb.org/files/4674/Stern_2003_The_Simpsons_Pinball_Party_Manual.pdf#page=8
Basically, any coil with the power line color of yel-vio.

I then went through the Dr. Pinball questions for a few of the coils in question.

The first few questions are the same regardless of which one I check.
1 - Does the coil fire when you tell it to. (No.)
2 - Is the coin door open and the power interlock switch pulled out? (Yes)
3 - Is the 20v or 50v led lit. (Yes.)

note - when I was answering the questions for the I&S ejector, it asked me to check the 20v led. For the others I checked, it was always 50v. If I'm reading the manual right though, it indicates that all of the coils should be 50v. No idea if this means a thing or not. Would have to double check to see if any others are tied to the 20v led if that could be important.

4 - At this point, it tell me to "Attach jumper wire from ground to metal tab of driver Q#" With the # after Q changing depending on which coil I'm testing.

I feel dumb, but I'm not sure what it's telling me to do here. I mean, basically, I need to run a wire from the transistor to the ground. But what ground? The braided stuff that runs through the cabinet? There's some in the head that would be easy enough to access. Or is there another standard grounding wire that I'm missing.

Also, what should I use for the jumper? Would any old piece of wire do? Or should I get a few alligator clips and make my own?

Any advice/help with this would be really appreciated.

Also, any top of the head ideas on what I'm facing here? If one coil went dead - could it effect a bunch of them at once like this? I'm really hoping it's something as simple as replacing a coil and not the entire I/O board, but I have no idea about these things. The burnt smell makes me assume the worst, though it does seem to have emanated from the body of the machine and not the head.

If any pics or additional information would help please ask. I'll respond as quick as I can.

Thanks to both of you. Too late tonight, but will do so tomorrow after work.

Forgive me, but would a blown fuse account for the smell though?

Well, full disclosure - I have to hit a store on the way home from work tonight to grab a multimeter. Don't actually own one. Been years since I've used one too, so a couple youtube videos shall be watched before hand.

Regarding checking fuses - any particular ones to check, or just check them all? The inside cover of the manual has a list of them all with their locations - shouldn't be a problem if needed.

Well, that was actually pretty obvious. Hadn't looked close enough last night, but one of the fuses (F21 - coils) was pretty clearly blown out. All others triggered the continuity sound on the multimeter.

Mini celebration quite short lived. Replaced it and it immediately blew again upon turning the machine on.

So I assume the next step is the check the resistance of the coils that weren't firing? Did that, and found 8 of the 10 registering between 10-12 ohms. The Itchy and Scratchy coil was up at 16 or so. And what I assume is the culprit - the bottom bumper - which I could only get a reading of .3 on.

Am I on the right track here?

Next step if so? I've read that it might just be the diode on the coil and not the coil itself, but have also read some things stating that you should just replace both at the same time regardless? Wouldn't it have a related transistor on the I/O board? Anything to worry about there?

Thanks Lloyd.

Will do and report back.

OK. Lower bumper coil disconnected and wires taped off. Per the phone call (Thanks again!), I also disconnected the related power line connection from the board. (Plug J10)

I replaced the fuse again and powered things on. No issues. Fuse was fine. Powered back down and plugged J10 back in and powered back on again. Fuse was still fine.

I'm assuming this is a clear case of needing to replace the coil that I disconnected? (Or if I remove the diode from it and find that it's faulty - replace that diode?)

Here's what's confusing me though.

Per my first post - when the fuse blew, none of the coils using the yellow-violet wire for connector J10 would fire. Makes sense, as I can see in the schematic now how that should have been the case. But once the fuse wasn't blowing, I assumed that things would go back to normal other than the one bumper not working. Is that not necessarily the case?

When it was powered on, the machine says that balls are missing (They're not.) and goes into ball search mode - firing off a number of coils. The timers hits zero, and the display basically goes into attract mode. When I hit the start button though - no ball gets ejected to the lane.

I checked the switch test, and the switches for the balls in the trough were showing as active.
I went through the coil tests and found that most of the previously effected coils would fire, but others wouldn't.

The three coils for the upper playfield all fire, as do the right and left bumpers.
The disconnected bumper doesn't fire of course, but neither do the remaining 4 - the I&S eject, the drops reset, trough upkicker, and auto launch. Is this surprising? I have no idea.

Was just about to edit my post - I was able to get all of the balls out of the trough, and dropped them back in while the machine was in ball search mode. It no longer thinks that the balls are missing.

Yeah - the coil that was disconnected had two wires leading to one lug. Yellow-Violet, of course. That's actually what I meant when I called to ask about connecting them but I don't know enough to make myself clear. Was pretty sure it would be crazy to connect the other wire - but was unsure about the two wires leading to a single lug.

Welp - as if you weren't a legend already. Two wires from the one lug connected and everything is firing as expected. Thanks for everything. You have a favorite beer or adult themed beverage? Would love to bring you something for your trouble on Sunday. (Or a favorite dog snack for Prada?)

(Thanks to Phatchit and dendoc as well.)

Well, if you ever need carpet torn out again..... I will hire someone to go in my place. I think I'm still sore.

Argh.

New coil came in the mail today. Just installed it and wired it up. Turned on the machine and everything seemed normal. Decided to run a coil test before playing a game, so I opened the coin door. When I pulled out the power interlock switch the coil that i just replaced fired off.

I just stared at it like a fool for a bit wondering what had happened when I saw a tiny bit of smoke coming out of the bumper. (A cool mod since the bumper is a nuclear tower and all, but not really.) Powered things down instantly.

Since then - I've checked the fuse that had blown when this issue cropped up - Still good.
I checked the resistance on the new coil - reads around 11.0.

I double and triple checked that I had wired the coil properly. It's identical to the two other bumpers in the group, exactly how I remember it from when I took the old coil out, and per the manual - If I'm reading it right - it's wired right.

Here's one of the other bumpers:
20150123_200538[1].jpg

Here's the one I just installed. (I am terrible at soldering, but both connections are solid enough that they withstood a good little tug on the wires.)
20150123_200451[1].jpg

When I took these pictures - a good 10 minutes after the smoke - the brass(?) bracket that the coil is mounted in was actually warm to the touch.

Again - I'm 99% sure that I didn't wire this thing in backwards. A couple bits from the manual.

Power supply line to the banded side of the diode. Transistor line to the non-banded.
coil-wiring.jpg

Power line - banded side - yellow/violet, transistor line - non-banded - blue/orange.
coilwiring2.jpg

This matched both of the first two pictures. (As well as the third bumper in the group.)

Some help here?

Ugh again. Was just reading on how to test the related transistor.

And looking at my soldering "skills" - that's a house call. I'm not touching the power board.

Edit - off to test it. Transistor Q11.

Hmmm. Continuity test - black lead to the ground in the backbox, red lead on the transistor (At least on the large metal part in the front) - and I get a constant tone.

I thought that was what I wanted to hear, or do I have that backwards? Or is that just 40+ years of experience talking?

Not that big a deal, I guess - It's a $3 part at pinballlife. Just disappointing, and a matter of paying someone to make the swap for me.

Edit - yeah. I'm getting a tone, but the reading is roughly half of what the other transistors for the coils that had previously gone out are getting.

I would really like to get better at it. I think I'd rather get a piece of garbage circuitry to practice on first though. Messing up a board in my old table would just depress me way too much.

Thanks, Lloyd. Will be coming there Sunday regardless if you have the time. Anywhere local to buy them? Can certainly just order through the mail and come out there when it arrives otherwise, or if you think Sunday will be too busy.

As annoying as it has been for me - I agree entirely.

Cool - could only think to check radio shack and it looks like they don't carry the 22NE10L or IRL540N.

Understood about Sunday. Less soldering, more cheese pumping. Pick a day and I'll be there with the board. Can talk to you about it on Sunday.

I probably forgot to call my mom on mother's day last year.

(I obviously have no idea myself. Would love to know. I mean, the chain of evens kinda baffles me. Fuse blows, all signs point to issue with the coil, but replace the fuse and the coil and then the transistor is bad? Or I assume it was bad all along - but then why was I getting basically no resistance on the coil? The nerd in me is honestly enjoying learning this stuff, but damn. I am seeing the allure of HUO and NIB, that's for sure.)

LTG to the rescue. Transistor replaced, board reinstalled, and all is well.

Ah ha ha ha. Put everything together - made sure it was working - went to dinner.

Came home and decided to play a game. By the end of ball one of the first game the upper right and upper playfield right flippers were not working.

Fear not. This is getting to be old hat.

Tested the coils - all firing as normal. Check the damn double leaf switch (or whatever it's called) for the right flipper button, and the second stage that controls the two upper right flippers wasn't making decent (if any) contact. A little gentle bending and finger crossing later, switch appeared to be making contact properly. Start everything up and bingo. Back to normal again.

Proper vote for the original poll = choice B. Welcome to pinball ownership.