Thanks for posting this up George.

I looked over the various boards, etc and don't see any signs of burning melting, etc. I didn't notice any other fuses blown either, but I should look again. I put in Comet single LED's #44 style bases. They work fine in the Back glass area.

All was well until I got into the pop bumpers. After we found out the game wasn't advancing a ball, ball poppers were not working, targets stayed down we found the blown 1 amp playfield fuse. Checked the game over and reinstalled a new fuse, start up seemed to go well, targets popped up etc and then I got a whiff of electrical smell and a wisp of smoke. Shut the game off. When we lifted the playfield I found the left pop bumper coil assembly to feel hot - the metal bracket that holds the assembly hot to the touch. Everything else seemed ok - thus my thinking that that coil heated up making that bracket hot. The others were cool to the touch. Nothing else seemed unusual.

( Side Note: ) Only other thing I did see is the assembly in question is missing the end nut stud on the end of the rod assembly on one side under the fiberboard at the plunger area - but I think that happened a long time ago as I found the nut with a little thread in the back end of the head of the machine when I cleaned it out along with miscl burnt out bulbs etc - the service grave yard if you will for the machine. I would guess this has been secure enough and functioning minus the broke nut for along time and not related to my issue, but When I change the coil I wonder if I should put in a new rod assembly and nuts... see second picture, right side missing broke off stud end and nut.

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Took some photos this morning when I did an additional inspection inside the control area in the head. I didn't notice anything unusual to my untrained eye.

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Here are some more shots I just took.

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and pics of the bulbs I put in and the Pop bumper in question from the top side - for reference of position

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Did pulling on the lamp socket make the switch close thus locking the coil on? The sockets are not suppose to move.

Grumpy - the socket ( gray area ) did seem to move up but not any further down than in the picture. The stock incandescent bulbs were put back in. They were in that position for the caps to fit back on. If raised further up the bulb strikes the cap.

The left and upper pop bumpers work in unison. When the bumpers alternate, those two go off and the right lights alone in game play. Only the the left low bumper coil assembly became hot if that helps diagnosis.

First off, what you want to check is how the thumper bumper lamp socket is secured (or not secured). From the factory, the lamp socket lugs are normally bent at a 90 degree angle to the edge of the playfield and then stapled down. After that, they solder the wire to the stapled down lug. Often, when someone had to service the bumper for any reason, they remove the staples and this may have allowed the socket to slide up and down. Which in turn, may have allowed it to touch the metal of the bumper bracket.

It should not have been able to encounter the spoon switch blades. Regardless, the software is "one shot" for the closure of the switch and should have only fired the bumper coil once.

However, it does sound like you have a shorted drive transistor for that bumper and possibly a melted coil (especially if it has a nylon sleeve). Thus the reason the 1 amp solenoid fuse blew (and maybe re-blows). You can unsolder the single wire to the left pop bumper and replace the fuse and see if everything else is okay except for the kicking of that bumper.

Also seeing the original ROMS and possibly the original sockets, I would look into having someone replace the ROM and RAM sockets if you continue to have any odd lock up issues with the game during play.

Ugg. Sorry, I didn't open your first photos. I didn't know Stern used metal mounting plate for their bumpers. So, disregard the staple/wood thing above. It looks like they used a rubber grommet in the metal plate to insulate the lamp socket. Only the solder blob would be there to hold it from moving up and down.

As to actually using LED's, might I offer up my ready to go solution?
http://www.siegecraft.us/presta/index.php?id_product=44&controller=product&id_lang=1

The ones in the back glass work fine. I am going to stay with the stock incandescent lights in the thumper bumpers. I probably messed up trying to put LED's in the Thumpers either by leaving the power on while I did that and/or the sockets moving. Staying with the stock lamps in the thumpers is fine. I'm not rebuilding the game. I just wanted to add a little more light and use cooler bulbs to help preserve the back glass etc.

The ISSUE is figuring out what happened and getting the game up and running again. I suspect the coil may now be bad and am wondering if there is anything else I should look at or check. Is there a way to check the coil before I remove it? I have ordered a replacement for the coil and a new rod and ring assembly since the right stud/nut is broke off.

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Would I unsolder the orange lead and/or also the second lead also to the coil ? Would I need to do anything else or unsolder anything else at this assembly ? (Of course electrical tape the ends once the ends are unsoldered) - I should be able to see then if the game runs normally, minus the one bumper operating ? Will the game work with one dead bumper - is that ok to do ? Again I'm a newbie so bear with my questions.

Edit Additional: I raised the playfield and checked if the Ring and Rod "pop" or move up and down freely, the effected one does not - it tends to stick , the other two move smoothly. Thus I believe the rod and ring stuck down overheating the coil - I'm thinking I need to change the coil and coil sleeve. I pushed down on the rod and ring and here you can see it stays stuck in the down position viewed from the top of the playfield...

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I pushed the ring assembly back in the up position. I turned the game back on and it started normally, targets came up, ball advance sounded like it was working, ready to play. I let it run for about 1 minute and turned the game off. I raised the playfield and the coil in question was warm to the touch. The other two cool. I now believe I just need to change out the coil in question along with a sleeve and change out the rod and ring assembly for another without a broke stud.

Disconnecting the single wire (not the double) is enough to let you play the game and yes, you can with one dead bumper.

Keep in mind, more than likeky, you managed to short out the drive transistor for that bumper coil (on the solenoid driver / power supply board). So, when you go to replace the coil, if when you power it up it immediately turns on, you will need to change the transistor (TIP121TIP122,TIP102 etc.).

Pay attention to which wires go to the stripe on the diode. When installing the new coil, reattach the wires that came from the stripe to the new lug with the stripe. Dont just transfer the wires based on postion. If you hook it up backwards, the first pop will short the diode which in Turn will short out the TIP102 again.

On the coil, you should be able to test the ohms with a meter and compare the readings to a working coil of same values. Isn't there a diagnostics menu in that game? I'd be looking at those too, specifically the diagnostics for switch/light matrix and solenoids. I think I'd remove one wire from the bad pop bumper coil (or remove the pop bumper fuse if it has one) when running any tests to keep the damage from getting worse. The tests will give you a direction to go to locate the issue. Keep in mind that what you see now may have been caused by something else you see or haven't seen yet. Here are some general possible paths to look at,

Light matrix shorted to switch matrix =
a) blown fuses
b) cooked/shorted control light transistors, or
c) shorted gates in the switch matrix IC's, or
d) burned coil, cooked/shorted driver transistors, or
e) all of the above

Light matrix shorted to coil voltage =
a) blown fuses
b) cooked/shorted control light transistors, or
c) burned coil, cooked/shorted driver transistors, or
d) all of the above

Light matrix shorted to ground =
a) blown fuses
b) cooked/shorted control light transistors
c) all of the above

Steve

@ CactusJack, dead on. If I'd have known you had a post while I was making my long winded post, I wouldn't have posted.

Steve

Do you have an ohm meter, if so then with the game unpluged unsolder the orange wire and measure resistance to ground. If resistance is low, you have a burnt transistor or a shorted wire.

I did disconnect the single orange wire from the coil and capped it with a wire nut . I turned the game on and it appeared to operate correctly other than pop rebound at that location. The light lighted and the yellow skirt did register points - just no propelling off the bumper when it struck the bumper in question. All the other features of the game seem to work. I ran a few balls through and had the game on for about five minutes. I turned it off and detected no other problems, warm components etc. I am hoping that changing the coil, sleeve and changing out the ring and rod assembly will do the trick. Now I will wait for parts to arrive...

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I'd definitely replace the coil driving transistor, maybe the pre-transistor too if it has one.
CactusJack gave great advice, blownfuse' list of probables is excellent too.

your post about coil getting hot in up position sure sounds like a burnt transistor to me.

If you only change the coil, it will overheat again! You need to trouble shoot your problem still.

I am really Green and a total NEWBIE on this. It's probably been 40 years since I had some shop class in school with electricity and the first time I have been inside a pinball so you have to bear with me. I should have a multimeter later in the week along with a coil, sleeve and a pop ring.

I do have the wiring diagrams and a brief manual for the game.

The game does have a self test feature. I ran through that once, before I had problems, while I was resetting the high score feature when I got the game, so I could figure out how to do that again if it's any help at this point.

How do identify where/which transistors and can I test them and how ? ( I did post photos of each board earlier in the thread - I can get closer photos of any areas) ( could also snap photos of the wiring diagrams if that helps too )

If you want to send me a PM, I can probably stop by sometime & give you a hand with locating the bad transistors & replacing them. I'm George's brother & also live in Grafton. I can't tell from the schematic what parts the predrivers are (maybe someone can chime in), but I've got some TIP102 which should work fine to replace the SE9302.

Looking at the schematic from the IPDB.org it unfortunately, has the schematics split down the fold and the info you want it split between two pages (pages 29 and 30). On the solenoid driver board (the one with the large metal finned heat sinks) you are apparently looking for Q9 (one of the larger metal tab transistors) Back then, they used all sorts of numbers. Mostly Tip120,Tip121,Tip122 but I have also seen SE9302s. Of course, today's replacement would be a TIP102.

To test, with the game off, remove the connector across the bottom and the one over on the lower left (of the solenoid driver board). With a DVM set to its lowest ohms scale (usually 200 or less), use one of the mounting screws on the edge of the board, or the ground braid down at the bottom of the head for your black lead. Then, with your red lead, take a reading from each silver transistor tab. You should find one that reads almost a dead short or at least a very low ohm value. If you do, that is your shorted transistor and will need to be changed by someone that can handle PCB work without doing more damage. It is also possible that the pre-driver is bad but those are contained in those smaller ICs (CA3081?) on the same board.

Thanks VERY much - PM sent.

I did run the self test a few minutes ago.

All good with the exception of solenoid 02, which makes sense, left thumper.
All switches tested OK.

Cactus Jack again thanks for following along with this thread. Greenhorns like myself need all the help they can get !

Here are some close ups of what I think we want to examine .... ( at least I can take decent photos )
First shot should show Q9

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You can even see that little solder sweat bead alone the top seam (Q9) That often happens when the transistor overheats or shorts out.

Good Eye - I see it now that you point it out. When you enlarge the picture I can see the little bead. Thanks for the lesson. Visual stuff I can grasp.

On my T3 the diode on the shooter coil went and it took out the transistor and fried the coil. So I think it took out your transistor too.

boustrophedonic came by and gave this Greenhorn a Big assist and changed out the transistor at Q9 for me. He had the board out and on the operating table lickity split , performed surgery and transplanted in a new transistor. Board went back in in short order.
THANKS FRED !

Hopefully I will have the parts I ordered later this week and will give a whirl at changing the coil, sleeve and rod and ring assembly.

( I also ordered a couple spare predrivers a few minutes ago in case those happen to be needed or fail at a later date.... also ordered some spare transistors )

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I forgot. Bally used to tell their operators that you could use one of the Bell Chime coils as a spare to get your game back up when on route. I can't remember if Stern also used the same 27-1000 coils on their bells or not.

The long bell on a Bally was only used for one note on the start up tune so it typically wasn't missed by anyone.

good deal NoQuarters, awesome boustrophedonic got your board ready for the new coil.

Stingray is now back up and Running !

Parts came today so the coil got changed. The old one's sleeve was apparently melted some and that is why the pop ring was sticking. So didn't have to change the ring. My son gave me a hand and we got the coil changed out successfully.

Coil and transistor appeared to have done the trick. Thanks all for helping with the diagnosis. And a special thanks to Fred for the house call and changing that transistor !

Now to play the game again.