(Topic ID: 293848)

Gottlieb Big Shot Repair

By Flip-it-good

2 years ago

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There are 211 posts in this topic. You are on page 1 of 5.
#1 2 years ago

Hi everyone, found a Big Shot in nice shape. Before I turn it on and see what's working and what's not, there's a strange yellow wire that seems to go from one end of the fuse to the lowest set of stacked switches at Position #1 on the score motor. Not sure if this replaced a damaged wire (there's an original wire already there) or it's a hack of some kind. I have the original schematic but wanted to perhaps get some advice before I fire it up....many thanks!
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#2 2 years ago

From your picture, it appears the yellow wire is connected to the same 2 places as the black and yellow wire. Maybe the original cloth black and yellow was not working and the owner just installed a new yellow wire? Just appears that switch is a black and yellow other end of the fuse is black and yellow and the yellow wire runs the same 2 places.

#3 2 years ago

Ok, I took the wire out for now. First step: Fired it up today. We have power but no lights. Backbox and playfield are dark, replaced all bulbs with new....fuses all check good.

Game credits up from the backbox using the credit unit along with a knock from the knocker coil. Score motor just keeps turning at power up. At first, Player 2 score reels reset to Zeros and Player 1 got 3 of 5 reels to zero. So there was some action earlier today, but now, just the turning score motor. I tried taking all of the score reels out of zero position manually to see if that would do anything at game-start, but no change.

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#4 2 years ago

Update: after resetting the large switch bank up front manually, the score motor stopped and I have backbox lights, tilt is lit but no playfield lights yet. Game still credits up, start button activates the score motor continuously but no game start.

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#5 2 years ago

The Player unit controls much of the reset sequence, including resetting the score reels, and activating the Control Bank Reset relay (U). Does the Player unit move when you reset the game?

Or If you'd like to try a phone call (and you have a paper copy of the schematic), send me your cellphone number in a private message and I'll make a first reply with a text message.

#6 2 years ago

Thanks Howard, I will check that later today...

#7 2 years ago

Here's a YouTube link to what's happening...

After resetting the large metal bar (main bank of switches) manually, SB and SB2 are the only two switches upfront that move when the start button is pressed. The game make sounds like it wants to start and the 'tens' score reel for Player 1 goes all the way around once from zero to zero but then just the score motor spinning....

#8 2 years ago

Gotta get that N relay unstuck. That's your 10 pt relay. In the snippet below, that relay is turned on by your kicking rubbers or any other 10 pt switch on the pf. Since your relay is locked on, I suspect it's one of the red switches. There are only 3 - the red one marked "N" is the locking switch that's actually on the relay itself - it's working since its job is to lock on the N relay, and that's happening. Look at that switch anyway to make sure that it opens when the relay relaxes. I'd guess the problem is one of the other 2 red switches labeled "ON ADD 1ST. TENS" and "ON ADD 2ND. TENS". Those switches are normally-closed switches that are on the 10's score reel for each player. They should open when the plunger pulls in and that should open the circuit and relax the coil. That's not happening, so I'd look there first. Use the wire colors to identify the correct switches on the score reels - look for a normally closed switch that the plunger opens when it pulls back into the coil.

That'll be a start.

Big Shot N relay (resized).JPGBig Shot N relay (resized).JPG

#9 2 years ago

For your control bank not resetting, the circuit that fires those 2 big solenoids at the bottom of your playboard is outlined in red. There's not alot to it - a 10 A fuse (and it's holder), a Motor 3C switch and a switch on the U relay. Is your U relay firing at all?

Big Shot control bank reset (resized).JPGBig Shot control bank reset (resized).JPG
#10 2 years ago

The very bottom switch on the "N" relay which has a purple white wire or purple yellow hard to tell, is always closed no matter what position the relay is in. The other side of that contact seems like it's jumpered over to the other stack on that same relay which has a pair of white/orange wires.

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#11 2 years ago

When I separate that bottom switch on N, all is quiet. Is that switch supposed to be closed at all times?

#12 2 years ago

Took a chance and separated that bottom switch by pulling the white grooved piece forward all the way and dropping the bottom leaf one notch. Now all the contacts connect at the same time and are open when at rest. I have a feeling that somebody was back here and may have bumped it so that the leaf got caught and went up one notch closing that switch permanently. All is quiet and triggering "N" fires the 10 point reel correctly. (See next pic)

#13 2 years ago
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#14 2 years ago

One of the 10-point switches behind a Target Bank was too close together! Every time I dropped the playfield into position and it caused a vibration it would trigger N!...That mystery solved.....Now I'm listening inside the cabinet and the Tilt hold relay "H" and the Hold relay "R" are energized is this correct?

The "U" relay does not fire unless I activate it. It then resets the main switch bank. I'll credit up the game, press start and the score motor will continually spin... once I reset the main bank by hand or activate 'U", the score motor stops. Playfield scores with every switch. Have backbox lights but no 'ball in play' lights and playfield is dark...

#15 2 years ago

Yes, the H and R relays are supposed to stay on. Hopefully, they're not too buzzy. So it sounds like you're getting close - you have to figure out why the U relay doesn't fire.

Good job with the switch on the N relay. Just as a general rule, switches aren't ever supposed to always stay either open or closed...there wouldn't be any point to having a switch then. They should always change state when a relay is energized - going from open to closed or vice versa. One of the nice things about working on an EM is that you can move the relay actuator by hand and watch the switches opening and closing to verify correct movement. Visual connection of the contacts doesn't necessarily mean electrical connection, but I like being able to verify that the contacts are touching or not.

If your playfield lights are out, you might want to check the lower fuse of the two shown (in red) in the snippet below - it'll have a white wire on one side, and a white-red wire on the other. Check that the fuse and fuse holder are both good. Or that yellowish wire that you took off in your first couple posts might be involved (although I think the wires that the yellow wire was connecting to weren't either white or white-red?) Anyway, check the fuse first.

Big shot pf light fuse (resized).JPGBig shot pf light fuse (resized).JPG

#16 2 years ago

I traced the Green/White wire that the "hack" yellow wire was soldered to from the score motor 1A (bottom stack) to what looks like a 'Match Unit' in the backbox. (See pics) Not sure what they were trying to do here. The other end of that hack wire has a solder blob on it but was detached. So I'm not sure where they had it.

Fuse was blown for playfield lights. Put a fresh fuse in and it blew instantly upon power up.

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#17 2 years ago
Quoted from Flip-it-good:

Fuse was blown for playfield lights. Put a fresh fuse in and it blew instantly upon power up.

Temporarily replace the blowing fuse with a fuse circuit breaker

#18 2 years ago

You have a short somewhere in that playfield light circuit. They can be kind of tedious to find unless you get lucky. Look very closely at every light socket and see if you can spot anything wrong - look for 2 metal pieces touching where they shouldn't be, insulation missing off wire somewhere, wires pinched really tightly..anything where metal is touching metal.

As HowardR mentioned, a 10A circuit breaker soldered to a fuse that you can just plug in will save you lots of fuses! I know most people don't just have those lying around, but if you feel like investing 20 bucks, they're very valuable for chasing down shorts without going through a million fuses:


I got lucky using a resettable circuit breaker one time, which took about 3 or 4 seconds to blow after the power went on. I put the breaker in, turned off the room lights, and then turned power on to the machine. I was able to see a small, bright glow under the playfield just before the breaker blew - pointed me right to the short. Might be worth a try, though a normal fuse might blow too fast for that to work. I think you'll just have to be patient and observant and track it down visually unless someone else out there has a better idea.

Who knows what that hack wire was supposed to do - if it was hooked to the motor 1A, then it wouldn't have anything to do with lights. I wouldn't worry about it for now.

#19 2 years ago

By the way, that unit in the backbox that you're touching is the player unit - not the match unit. Very important stepper, that one - routes scoring to the correct player, keeps track of which ball you're playing, involved in resetting scores to zero when the game resets.

#20 2 years ago

Ok, ordered a 7 Amp breaker from Amazon. Arrives tomorrow. Underfused it by a few amps as the article suggests. Thank you HowardR for that suggestion. I will begin the lamp socket/wiring search...

Does the ball have to be loaded for game reset to happen in this one. Trying to work on that as well....

#21 2 years ago

Found the short. Lamp base under the 8 Ball hole in the center of the Playfield had plenty of slop in the bayonet base. Clipped the wire, put a new fuse in and bingo! Looks like the top part of the socket separated from the base and was just flopping there.

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#22 2 years ago

Good catch on the light socket! Now to figure out why the U relay isn't firing....

#23 2 years ago

Really appreciate the guidance so far...tried playing a game and all the scoring on the playfield is correct. We now have ball in play lights. Still incorrect are when the ball drains bonus does not tally up and it does not kick the ball into the shooter lane for the next ball - if you push the ball through the tunnel to the shooter lane manually, it activates the switch in there and Ball 2 will illuminate. Finally, when you hit the game start button all but one score reel in Player 1 display go to zero (hundreds does not go to zero) and the score motor keeps spinning until you manually activate "U" relay or pull the main switch bar and reset the front rack.... after the 5th ball the game still scores on the playfield...no game end....

#24 2 years ago

Perhaps I'll clean all the contacts on the player unit, ball count unit and any bakelite rivets and shoes since this controls the scores resetting. Maybe that's the issue with the scores not returning to zero upon reset.

Not sure how to tackle U not firing. I have a full schematic and I'm going to clean all switch points today with a fine file to see if that helps...

#25 2 years ago

Here's the startup sequence from the Big Shot manual. Exactly how far does it get?

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#26 2 years ago

SB and SB1 fire on game start. S relaxes but SB1 stays active until I manually reset main bank or activate the U relay. Score reels do not reset. I did discover a missing piece of plastic on one of the leaf switches on the score motor. It should have been opening the switch but since it was missing that switch stayed closed all the time. Not sure what it does but I glued a piece of plastic on there and now it opens and closes as it should. (See Pic) outer most switch at top of Stack #2 it has a bit of orange rag stuck to it and has a double brown wire connected to it. That was closed all the time.
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#27 2 years ago

Newest video link...

#28 2 years ago

The player one 100 point reel switches are likely out of adjustment. Try pulling out the 100 point reel from player 2 100's reel and compare the switch positions to the player 1 100 reel as you cycle through the numbers. There are 3 positions for these switches: Position 1 at "0", position 2 "1-8" and position 3 at "9". Below is a link with some good pictures.


The bonus on this game is usually difficult to dial in. I've recommend the following:
1. Clean the rivets on the bonus stepper (under the play field) so that they look clean like the ones on your player unit. Also check the alignment on the stepper.
2. When a drop target drops it hits 2 switches. One is a switch the temporarily closes that triggers the immediate 500 points and a 2nd switch that remains closed and is used in circuit with the bonus stepper to score the end of ball bonus. Make sure the switches that remain closed when the drop target is down are clean.
3. If you are still having an issue you may want to check the travel of the plunger at the bonus unit to ensure you are getting 1 clean step each time it moves.

Also, is normal that the bonus unit steps 15 steps when each ball ends. This is the scan of the 15 pool balls for the bonus. Note the bonus stepper has two speeds...fast for pool balls(targets) not down and slow for targets that require scoring.

#29 2 years ago

Excellent feedback, thank you so much. I'm going to read through this carefully. I cleaned the bonus stepper today, nice and shiny. I did adjust the disc and it looks like everything's hitting correctly but I will check it again. All the drop targets seem to be working properly: a switch contact for score and then a contact for bonus lights. I will also check the hundreds reel and compare to player two. I was in there today cleaning contacts and I did notice there were three different positions, one at 0, one between 1 and 8 and then flipping over from 9 to 0 moving the arm inside. When the ball drains nothing happens... it just sits there, no bonus and it does not kick the ball to the shooter lane, you have to do it manually with your finger, it does register ball 2 when you do that though, so that's working....Also, game does not end after ball 5....

#30 2 years ago
Quoted from Flip-it-good:

When the ball drains nothing happens... it just sits there,

If the ball draining and sitting on the Ball Return switch doesn't activate the Add Bonus Unit relay (C), Inspect and diagnose this circuit with Alligator clip jumper wires
Example of a pinsider actually doing this https://pinside.com/pinball/forum/topic/red-baron-tech-question#post-5858156

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#31 2 years ago

So in the last video you posted, your bonus was (mostly) working....has that changed now?

#32 2 years ago

For your player 1 100's reel at reset problem, this is the circuit that's involved in the reset. The Motor 4A switch is working since other score reels are getting pulses to reset. That only leaves the P3B switch on the player unit (do you know how to find that switch?), and the 1st. "Hundreds" Runout switch which is on the score reel - and should open when the score reel reads zero. If you're not sure how the score reel switches should work, compare to the reel next to it, which is working correctly.

I'd guess one of those two switches is staying open all the time, or you have a broken solder joint and resulting loose wire somewhere in that circuit.

You're doing great so far! Finding that missing spacer on the score motor switch was a great find - that affects the timing and opening and closing of the switch, as you saw - so it's important that all those spacers are there. They drop off occasionally and are a bear to find and figure out....so good for you!

Big Shot 100's (resized).JPGBig Shot 100's (resized).JPG

#33 2 years ago

I have alligator jumper wires but don't know enough about how to use them as my EM experience is a couple of notches above novice.

I've had the player unit flipped downwards in the back box and I have seen all the cams and such in there, I just need to figure out which one is the P3B...looks like I'm looking for the switch with the orange/red wire. I will also check the hundreds run-out switch on the score reel. I'll resolder anything that looks suspect and report back... Thanks everyone up to this point, I really appreciate this and my 10-year-old will really really appreciate this!

#34 2 years ago

Here's a picture of a Gottlieb player unit (in the backbox). So P3B would be the 3rd plastic cam from the steel ratchet side, second switch up from the bottom. There's usually a screw in the upper right corner of the player unit that will come out and allow the whole unit to fall down 90 degrees on a hinge that will help you see things better, if you need to. OR-BL and OR-RED wires.

Player unit (resized).JPGPlayer unit (resized).JPG

#35 2 years ago

Using the alligator jumpers is a way to short parts of the circuit to eliminate switches from it. If the circuit doesn't work normally, then works when you've jumped some switches, then one of the switches you've jumped is the problem.

For example, in the bonus circuit for your machine that Howard posted, the idea is to fire the C relay. You do that by making a connection through all the switches closing between the left and right vertical lines, which are 28V power lines from the transformer.

If C isn't getting power, then one of the switches Howard marked in red isn't closing. If you hooked the ends of your alligator jumper to the green "X's", you would be shorting all the switches between those 2 points. If C suddenly fires, then you know one of the switches you have jumped across was not working. If it still doesn't fire with the jumper in place, then the problem is one of the switches to the left of the left green X. In your case where the "Ball Return Switch" was dirty, the C relay would have fired, so you'd know the problem is one of the 4 switches between the green "X's" that you jumped. You could move the alligator clips around to narrow your search. But you're always just jumpering over switches to try to find the one that isn't working.

Big shot bonus circuit (resized).jpgBig shot bonus circuit (resized).jpg

#36 2 years ago

That's so weird to see that somebody wrote with pen on the schematic that was posted, right below that red line "QB2 Mar-Or on ball return" My schematic has the same scribbling on it, most likely gottlieb forgot to put that switch in the schematic and vendors hand wrote it in...
When I get home tonight I will check that cam gear switch and jump the switches between the X's and report back... Note: I checked the contacts switches inside the hundreds score reel and they were indeed not closing and opening correctly. Thank you bonzo71 for the link to the open-closed adjustment chart for the Dragon Unit! One contact was not opening and the other one was staying closed when it should have opened can't recall which one, but I had a look at it this morning and adjusted them accordingly. The little arm inside there with the black rubber insulation over the top was sort of bent and not moving those switches left to right as it should. I will also re-inspect those tonight with my multimeter to see if there is continuity when needed at points that should be closed.

#37 2 years ago

Okay I pulled down the player unit and cleaned all the points on that third cam switch...checked the spacing on the hundreds reel and everything looks okay. Although, I have nothing to compare the switch at the player unit with anything so I don't know if those contacts are correct but they seem to shift correctly when the cam comes by. Upon restart the hundreds real does shake a little bit like it wants to reset. It didn't used to do that before.

I see the green X's, I have one lead of my alligator clip connected to the black yellow wire on the ball return switch I'm having a hard time figuring out where that other green X is to the left? There are no wire colors and I can't figure out what that item is to connect it to....

#38 2 years ago

You might try cleaning the contacts on the score reel switches. I use a metal Revlon nail file with a rubber handle.

#39 2 years ago
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#40 2 years ago

Score Reel Photos (top to bottom)

Zero: Closed-Open-Open
1-8: Open-Closed-Open
9: Open-Closed-Closed

Switches filed clean...

#41 2 years ago

Regarding your jumper wire, the green X on the right is on the other side of the ball return switch - should be a RED-WH wire.

According to the schematic (ignore the hand-drawn part for now), the left X should be a SL-BLK wire on one side of a switch on QB1 - not sure what the other side's wire color is. Hopefully, you can find it.

#42 2 years ago

I guess I just don't understand wher to use the jumpers, I'm drawing a blank when I look at the schematic as to where the jumper should actually go...I understand the why, to bypass certain possible faulty switches....can't see a slate/Blk wire on QB1 (game over relay)

#43 2 years ago

The center switch on the score reel is used in the reset process. Although it appears properly ajusted, you could try pulling the reel out during reset and applying a bit of force on the center switch contacts.. or stick a metal file or a flathead screwdriver between the two switch leafs. Getting that reel to reset might cure the issue with the ball not getting kicked out to the shooter lane.

#44 2 years ago

I'll try it...I have a nice crowbar handy! Lol!
Rather than stick a screwdriver in there, I actually used a jumper and here's what happened...

#45 2 years ago

So if these contacts on the hundreds score reel are adjusted correctly, where does the hundreds score reel get it's pulses or power from?
Maybe the problem is there if I back trace it one step... But then again that doesn't make sense because all the other reels are resetting and according to the schematic motor switch position 4A supplies that connection so if motor 4A is working for the other reels it should be working for the hundreds reel. Just did a continuity check on the P3B switch there are five separate switches in that stack and I tested them from the top where the wires are soldered on while they were closed. Continuity on every one. Now whether they're opening and closing in the correct sync when the cam comes around, I don't know. I don't have a chart but they seem to be acting like the other ones.

#46 2 years ago

Here's something crazy, I just took Q relay out, ball return control relay and cleaned it very well and adjusted the contacts. They didn't seem quite right and now all the reels reset to zero is there a tie-in there?

So before I mess anything up let me move to the next step.... When the ball drains it doesn't score properly, sometimes let's say four drop targets are down that should score 4000 when the ball drains but it only does one or 2,000 sometimes....

See it here....

#47 2 years ago

Not sure if I'm helping or not, but there's been a few topics about the bonus system for this game. I spent quite a bit of time adjusting and cleaning relays and nothing seemed to get mine 100% right until someone suggested adjusting the travel of the metal plunger that gets pulled into the coil on the bonus stepper. The adjustment is make by loosening the fasteners that hold the coil in place. Once loose, the coil can be moved slightly up and down. I had to adjust the coil so that each step advanced the stepper once. This stepper is very fast and sometimes is was skipping a position causing the bonus count to be lower than expected.

#48 2 years ago

That's good info, bonzo. I would probably make sure all the drop target switches that are involved in counting the bonus are making a good connection too. This will take some testing, but see if each drop target registers individually when counting bonus, or if there's some consistency with the miscounting. When you drop all 15 targets, do you always get the same amount of bonus? Or is it inconsistent?

#49 2 years ago

Hmm, certainly worth a try... In the last video all the reels went to zero and I was very excited but last night I tested a couple more games and its doing the same thing now, hundreds reel will not reset. Is there another line of connectors or switches that lead to that reel?

#50 2 years ago

For your bonus unit to work right clean all the rivets, check all the springs for the right tension and the coil sleeves are clean and coil plungers are clean.

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