Howdy!

I've had this machine over a year (bought it broken) and have finally accumulated the skills and time to hopefully get it working. It is Gottlieb's "The Games" system 80A. I have read https://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#System_80_.2F_80A_Power_Supply many times (I don't claim to understand it), and have the instruction manual with all the schematic diagrams too (don't claim to understand these either). Also for these tests the only connection to the power board (A2) is J1. I believe I have replaced most of the recommended parts on the power board (I did that work a long time ago, including transistor at Q3), and have double checked all the work.

The immediate problem: the 5V led is not illuminated and the game does not boot. I've been looking at the schematics and don't understand where the 5V is supposed to be coming from, so I am having trouble figuring out what may be the issue. The 12V led lights up fine, and the 8V at TP5 checks out fine. I get no reading at the 60V and 42V TPs. If I am reading the schematics of transformers output to J1 on the power board correctly, pin 9 is +8V offset (don't know what offset refers to, but since the 8V test point works I assume its all good), pin 7 is 60V AC, pin 8 is 60V AC Return, pin 1 is 12V, pin 2 ground.

So following the schematic from pin 1 on J1 I don't know where the 5V is supposed to be generated. I see it referenced on pin 2 of the IC1 Regulator UA723CN (I tested it with my meter and got about .5v, but all the other pins referenced were outputting what the diagram shows. But since I don't understand the directionality of these things (as in, should that IC1 be outputting 5.1V at pin 2, or receiving 5.1V at pin 2, or if there even is such a thing as direction).

I also see 5.6V mentioned around the transistor at Q3 2N6057. Is this where I should be looking? This is one of the pieces I installed new, and checked for continuity from the legs at R11 and R9 as detailed in the article, and there is no continuity between Q3 and the cold plate.

Also, I read in the pinwiki that (referencing 80/80A) "Unlike the System 1 power supply, the +5 VDC logic power is no longer rectified and filtered on the power supply itself. This process is now handled by a bridge rectifier and a large filtering capacitor located on the transformer panel.", but how can that be true if board A2 at J1 does not have a 5V input, but then the board has 5V at a few places! I do see 5V at connectors J3 and J2, but since the guide says to look for the LEDs illuminated with those unplugged, I thought that board A2 will generate this 5V.

Any help is appreciated! Thank you!

Note: Dont worry about that mess at J3.

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Thanks for the detailed reply! I had already removed the wires at J3, so did the tests with J3 and J2 disconnected. Also, I played with POT1 turning the machine on and off each time, and jiggled the “banjo wire” at pin 5 on J1, but no change. I’ll also order those parts once I see if I should order anything else.

Here are the measurements:
"E4": 15
"E5": .63
"E6" (should be same as TP4): .62

Issue 2 -- high voltage supply.:
"E2": .81
"E1": .81
Resistor R4, end closest to heat sink: .39
Resistor R4 opposite end: .39

I also measured at the J3 pins:
1: .39
3: 0
4: 0
5: 0
6: .63
7: .63

Similar readings at J2

Thanks!

I took the plate off to check all my work, then just stuck them on there for testing purposes so I didn’t lose them. I was worried about tightening them down (from the back) if had to remove them and Q3 again. Would those screws effect anything for these short tests?

So, update! I flipped the screws and tightened it down properly, then fired up the machine. There was a slight hum this time, and smoke came streaming out of E6! So...?

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I am positive the smoke came from E6. Also, I turned the pot down while it was off. Now I get no smoke, and the 12v light is no longer illuminated.

Also, by insulator do you mean a bit of paste and a very thin plastic sheet? Cause that’s what I’ve got

That’s a last resort. I love to tinker!

That was my first guess too, but now the 12v is out. Also, behind Q3 is a very thin clear plastic looking piece the same shape as Q3.

I took updated measurements, and maybe noticed something peculiar?

New readings:
"E4": .11
"E5": .47
"E6" (should be same as TP4): .47
Issue 2 -- high voltage supply.:
"E2": .46
"E1": .68
Resistor R4, end closest to heat sink: Fluctuates .16 to .03
Resistor R4 opposite end: .03
For the heck of it I tested some of the screws that mount the plate to the brackets on the back of the light board, (Not the screws attaching the pcb) and they each had a reading of about .35

I did the ground mod like pic 2 months ago (this is not a pic of my board).

Is it time to yank it out and remove Q3 again? I do fear for those pads a bit.

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Thanks! I like everything except the back pain! This is my first machine. Since I got it I’ve acquired and fixed like 12 arcades and learned a lot, but they were less complicated. I got it for $250 and parts are cheap, so really nothing to lose.

Will do! I’d just like to order a bunch of parts at once to avoid $5 shipping a bunch of times.

Thanks! So just so I’m understanding, I’ll remove Q3, which has nothing to do with the higher voltage, and work on the higher voltage first. Plus check my work on everything else and find the source of the smoke, then leave Q3 off to do all the high voltage testing?

Also, is the fuse you referenced one of those in that line of fuses in the main cab? I think I have a bunch extra of those.

Thanks!

1 Looks like I was lazy trimming some ends of parts I replaced and they scraped the cold plate. I checked a few of these places on the cold plate and got continuity across the plate. None of these scrapes are located at or near E5 and E6 though. I trimmed them right up, but I guess no reason not to replace r12 anyways right?

2 Maybe alarmingly, I can get continuity between all 4 of the holes on the cold plate of Q3 (2 for soldering, 2 for screws). I assume the continuity from the screws is ok, but from the poles!? I wouldn’t know how to fix this. Some type of paint? New plate? Electrical tape? I guess when I checked continuity from Q3 to the plate I should have tested it to some exposed silver Area I should make somewhere safe?

3 I do not get continuity from those metal rings at the through holes for Q3 to the solder-side of the board. I noticed this several days ago, but when I used enough solder with Q3 in place I got the continuity needed. Any advice here? Flood the back with solder around that ring?

4 I don’t see any damage to parts on the part side.

5 continuity from all the pins at J1 is good to the traces on the solder side.

6 all the soldering looks fine and continuity checked out for all parts.

7 I attached a pic of Q3 and maybe the insulating piece.

8 Fuses F2 and F3 we’re both blown (I put them in new when I originally got the machine). I replaced them, put A2 back in with the cold plate but no Q3, and it was dead to the world. No lights on the playfield or humming. Then after a few minutes I figured out I was a silly turd and didn’t plug that black fuse in fully. I powered the baby back up, and BINGO, 12V is back online!

New readings:
"E4": 15.25
"E5": .63
"E6" (should be same as TP4): .62
Issue 2 -- high voltage supply.:
"E2": 22.2
"E1": 22.5
Resistor R4, end closest to heat sink: 22.4
Resistor R4 opposite end: 22.9
J3 pin 1 24.3
Screw of plate to bracket .17

What should I replace and or check? Replace Q3 and make sure it’s for the correct insulation, and somehow repair the cold plate continuity issue? Solder jumpers to Q3 for testing purposes and avoid the plate? If I’m pulling something out for testing, I’d rather just replace it! Plus I may not have the tools to test it properly.

Thanks!

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AC voltage CR1 banded end to non banded C4: 25.2

Also, here is a pic of that Q3 spacer I have.

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I’m having trouble taking the measurements. I think lugs are those metal pieces with wires soldered to them coming out of both top sides of the transformer?

Nothing is labeled on the transformer itself, and I am having trouble reading the schematic. I’m not sure which drawings corresponds to the transformer itself, and I see way more numbers on the schematic than actual lugs. Should I be looking to the right of that dashed box labeled 23836? I see two lines, labeled 1 and 2 that say 60V (and line 1 mentions F3 too), but I don’t know how these numbers relate to the lugs.

So in AC mode (with J1, J2, and J3 disconnected from A2) I connected what I would think would be lugs 1 and 2, on adjacent lugs (I checked all 4 corners of the transformer if that makes sense). The best reading I got was a couple 30s.

I also checked some combinations of fuses, and got 28v when I measured F1 and F2.

Can I get some help with what to poke, or how to interpret the schematic?

Thanks!
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After some gentle cleaning I could read numbers on the transformer, but none of them were 1 or 2. I’ve attached a pic of my drawing.

Also no brown or grey wires. There is a white wire with grey stripes on the end of the fuse F3 closest to the transformer, but that wire goes into the base of the platform the transformer is sitting on.

Might these numbers help me read the schematics at all? Is my best bet to cut all the zip ties and follow wires from J1?

Thanks!

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So, from the schematic above of the transformer, starting at A12J3/A12P3 I was able to identify both the 60volt lines.

Line 888 (gray gray gray) goes from A12P3 to F3 fuse, as in the diagram, then on the other side of the fuse changes color to 100 (brown, black black) and goes into a hole in the platform supporting the transformer.

Line 111 goes from A12P3 to that same hole in the transformer, and I don't see it anywhere else.

I have no idea what those lines are doing in there, where/if they come out, and where that is even shown on the schematic.

So, I put one end of the meter at F3, and touched the other end to every lug on the transformer. They all registered 0. Next, I tried about 20 combinations of random lugs on the transformer. The highest I was able to conjure was 50, but I certainly didn't try all combinations.

I don't know what to try next.

Ok big update! I don’t exactly understand what you meant by checking the voltage at pins 7 and 8 on A2 J1, because all of A2 is unplugged and would read nothing, so I think you were telling me to insert something into the A2J1 plug and check measures that way?

Either way my meter probes wouldn’t fit inside, so I checked the F3 fuse... And it failed! I put a new one in two days ago, but I must admit I didn’t test it before I put it in. I also looked at my previous posts and couldn’t figure out how I may have blown that new fuse. So I replaced it with a new one, and got much better measurements!

AC voltage CR1 banded end to non banded C4: 62

high voltage supply.:
"E2": 64.6
"E1": 82.6
Resistor R4, end closest to heat sink: 64
Resistor R4 opposite end: 64.1
J3 pin 1 64
J3 pin 3 46

I didn’t really do anything to fix this, but maybe a juggled plug or connection like you mentioned. Looking good? Next steps?

Bueno! I’m assembling a purchase list, and I’ll confirm it here. Is there anything else you recommend I buy just in case? It’s quite possible other parts of the machine will have issues.

Also, for replacing the pins on A2 and the plug heads, if I cut the wires, they will be too short to reach the connections. So should I cut and extend them, or get some type of pin extractor to pull them out of the plug? Or does that defeat the purpose?

I'm not sure which crimp contacts to get. I tried to read up, and saw conflicting info. Some said not to use Trifurcon on edge connectors or Gottlieb machines? Also, I couldn't find the AWG in the manual, so what size should I get?

I've also attached a pic of the crimpers I have (neither of which I have used very much). Thanks!

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Thanks! Cart is all assembled, but the keying plug only has 1 in stock. Do you have a recommended replacement? I'll place the order once the shop opens back up!

Ok, here’s where we’re at. Got the new parts. I installed the new Q3 with the insulation pad and plastic spacer thing, and replaced the pins on the board and wired new connectors (my first time!) for board A2. I also made a better connection on the through holes for Q3 to the solder side of the board.

I fired the game up, and got a tiny bit of smoke for a brief moment from the same general area as last time, just much less, and do not have 5V or 12V led illuminated.

I tried to reflow Q3 on the parts side, but no change. I also checked continuity from Q3 to some resistors, and it’s soldered in properly. I also gave all the wires a jiggle, and checked for continuity from every component I could touch on the parts side of the board to an exposed portion of the plate by the corner, but didn’t get any continuity.

I also remeasured all the points voltage:

AC voltage CR1 banded end to non banded C4: 63.5

With meter grounded to TP3 -- what voltage do you measure at following locations:

Connection point labeled "E4": 1.4
Connection point labeled "E5": .47
Connection point labeled "E6" (should be same as TP4): .47
** because why not I also measured:
Q3 top: .36
Q3: bottom: 1.48
E3: 8.02
E4: 1.4
R17 top: 1.4
R17 bottom: 1.4
**
C1+: 82.6 DC and 182.3 AC (not sure if this is normal??
C1 -: 0 DC and AC.
(I measured the AC using TP3)
**

Issue 2 -- high voltage supply.
Also a series pass regulator but his voltage is set by R1 and CR5.
With meter still grounded at TP3 -- what voltage do you measure at following locations:
Connection point labeled "E2": 65
Connection point labeled "E1": 84
Resistor R4, end closest to heat sink: 64.4
Resistor R4 opposite end: 64.6

I also measured at the J3 pins:
1: 64.4
3: 46.6
4: 0
5: 0
6: .47
7: .47

Also, I am still reading about .2V DC at the screws mounting the plate. This doesn’t seem normal...?

Any suggestions? The only thing I can think of is to try to run it briefly with everything installed except the plate, or cover any suspicious spots on the plate with electrical tape.

Thanks!
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Small update. I decided to check the fuses inside at the main fuse box again, and F2 had blown again. So, I replaced it and fired it up again. There was a brief louder than normal hum, and a little bit of smoke again from the same general area. I rechecked F2 and it blew again. So why the hell not, I replaced it and tried it again, this time having my wife turn it on so I could try to pinpoint the exact location of the smoke. However this time there wasn’t smoke. I pulled the fuse, and it was blown. Any place in particular I should check on A2 besides the region of the smoke? I don’t fully understand the routing to arrive at fuse F2, but I assume it’s after A2.

I double checked, and the fuses I am using are 5A slow blow fuses.

Let me read up so I understand those terms a bit better. I have played with pot 1 a bit, but can play with it more. I’ll figure out which way is down and turn it all the way. I’ve got a few more fuses to burn.

Ok, I'm comfortable replacing all those parts (I guess except for SCR1, which doesn't seem to go bad?). I figure since I have to take Q3 out again I may as well replace a few parts while I'm in there. I'll also check the soldering you mentioned. I'll order another Q3 just because, but is there a reason to suspect the new one got fried? Also, please let me know about any other parts I should order. Perhaps its possible I put POT1 in backwards or something (I don't even remember if I put that in, or if it is original).

Thanks!

Some progress! I checked the soldering at POT1, and it was clean. However I checked continuity and got some between two of the traces, even though there was no bridge between the traces. I removed POT1 and checked continuity between the legs, and I was getting continuity. I figured either the POT1 was bad, or something fried it. I replaced POT1, R14, and IC1 (723) since they looked to be related to me.

I fired the machine back up, and now I get the 12V light, but still no 5V. Also, F2 is no longer blowing. (All the other fuses are good too). Here are updated measurements.
With meter grounded to TP3 -- what voltage do you measure at following locations:

Connection point labeled "E4": 12.1
Connection point labeled "E5": 1.6
Connection point labeled "E6" (should be same as TP4): .9
Issue 2 -- high voltage supply.
With meter still grounded at TP3 -- what voltage do you measure at following locations:
Connection point labeled "E2": 65.2
Connection point labeled "E1": 84.1
Resistor R4, end closest to heat sink: 64.5
Resistor R4 opposite end: 64.7

Q3 top: 1.67
Q3 bottom: 2.86

Also, after being on a minute or two the cold plate does heat up, and Q3 is soldered properly and no continuity to the plate.

Any suggestions? Replace Q3 again? I don’t know how to check if Q3 is being fed the correct voltage in the first place, but both my Q3 measures don’t sound normal, so I’d figure the problem is elsewhere. But then again if I’ve got to open it again maybe I might as well replace it. Thanks!
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Thanks again for all your help!

I checked the old POT1, and it was turned all the way down when I checked it for continuity.

I checked for continuity both at the screws that go through Q3, and the round portion of Q3, to the cold plate and nothing buzzed.

Voltage at both screws on Q3 to ground TP3 was 12.04

The voltages at the new IC1 were all on the money to what you mentioned except pin 10, which measured an anemic 2.8. Turning POT1 up and down had no affect on pin 10, but did change pin 5. In the schematic I didn’t understand what pins 3 and 4 should output.
IC1 voltages
1 0
2 1.51
3 .87
4 .42
5 2.5
6 7.28
7 0
8 0
9 0
10 2.8
11 12.03
12 12.05
13 4.06
14 0

Across R12 red to E5, black to E6: .80 DC

Where should I measure the 5V? TP3 to one of the uncut legs of SCR1?

First, I unplugged connectors to all boards. It was a Herculean effort, and some blood was drawn, but I won the fight. I powered the machine up and no change.

Next I cut the cathode as instructed and measured at TP4. It was at 5.04. I tried to move it up, but it maxed out at 5.6 like you mentioned it might. I then set it to 5V.

I was unable to re-solder the cathode because it was in so close to the board, so I ended up separating the board and replacing SCR1 and CR8. I put it back together, and still no 5 volt led. (Everything except J1 is still unplugged). I remeasured everything with the new parts (I did not move POT1 once TP4 read 5V):

Voltage at both screws on Q3 to ground TP3 was 12.04

IC1 measures:
Pin 1 0
2 1.81
3 1.16
4 .56
5 2.48
6 7.28
7 0
8 0
9 0
10 3.19
11 12.12
12 12.12
13 4.41
14 0

Across R12 red to E5, black to E6: 0

TP4: 5 (yay?)

Voltage at both screws on Q3 to ground TP3 was 15.4
IC1 measures:
Pin 1 0
2 4.54
3 5
4 2.5
5 2.5
6 7.28
7 0
8 0
9 .03
10 5.89
11 15.25
12 15.25
13 7.13
14 0

Across R12 red to E5, black to E6: 0

TP4: 5

I accidentally touched two of the pins at one point, and noticed the measurements changed until I powered the machine off and on again. That must have been why the first measures were not accurate.

Nope. Should I reconnect everything and see what happens?

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Left side of R18: 5
Right side of R18: 4.97

So you think the led is bad? Is it actually needed?

Thanks!

I’ll reconnect everything and see what happens tonight!

Alright, reconnected everything and fired it up. Two of the displays show something (pic). The number 2 is in the credits section, but triggering a coin manually does not change this number, and pressing start does nothing. Also, there isn’t any attract sound, and no coin door lights (don’t know if the bulbs are good, or if it’s a different issue).

I was able to do the sound test by turning on switch 1 on sound board A6, and a very pleasant tune played over and over again, like the manual said it would. Plus I checked all the fuses in the fuse box, and they’re all fine.

I checked power at the resistor at A1J1 and it read 5V.

I cannot get the self test to engage either. I believe it’s the red button in the coin door. I press it and nothing happens. I tried holding it for a bit, and pressing it, then the start button too.

I checked what I think is the slam switch, and it is closed. I’m not sure if this thread is related: https://pinside.com/pinball/forum/topic/gottlieb-system-80a-no-boot-displays-show-1-knocker-fires

The reset board is a mess, but I can just unplug that right?

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Ed is indeed doing gods work. No doubt about it.

Is the MPU board A1? I am in California and am certainly on the road to sending it in, but I’d like to monkey with it a bit. Is there anything in particular I should check, either on A1, or the pin itself that would prevent it from booting?

Nothing is obviously wrong. I cleaned the edge connectors, re-flowed some solder, and removed and cleaned socketed chips. No change. I'll message Chris! Thank you so much again for all your help, and I'll follow up!