(Topic ID: 227547)

Gottlieb Sys 3 Sol Driver running... ...sllooww...?


By Coyote

8 months ago



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  • 19 posts
  • 5 Pinsiders participating
  • Latest reply 7 months ago by G-P-E
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#1 8 months ago

Have an interesting(*) issue with a Sys 3 game. Here's what's happening -
The board seems to be driving things(*) in slow-motion.
To the naked eye, all bulbs look dim - even flashers. (Not JUST controlled lamps..) I can NOT put LEDs in - even non-ghosting bulbs will strobe horribly, the pulsing of the columns are so slow.
Perhaps once every three games, the game will 'miss' a switch activation. And it's different switches - not the same one.

Things I've ruled out, checked:
I've checked all lamp diodes - all report good on DMM.
I've swapped driver board; no change.
I've swapped CPU board; no change.
If I disconnect the lamps, it *seems* as if the game stops missing switches. (However, this is so random, it may be a red herring.)

Since this seems to be affecting flashlaps as well (perhaps coils, too?), and it happens regardless of driver or cpu board, it's gotta be something in the game. the game is my #nudge-it, which literally uses 33 lamps, 11 switches (including cabinet) and 8 coils (including the flash lamps). It's a *simple* game. I've been tempted to take the playfield out and plug it into my #bell-ringer cabinet, to see if the problem follows the playfield or not. (The two games share many of the switch/lamp lines, and coils are identical, save for one, so I'm not worried about frying anything.)

Any thoughts on what to check next?

#2 8 months ago
Quoted from Coyote:

Any thoughts on what to check next?

You didn't mentioned if you checked the power supply...which is always the first thing to check. Not only check if correct DC voltage, but also check AC ripple level. Another thing: Have the proper ground mods been done to this game?

#3 8 months ago
Quoted from wayout440:

You didn't mentioned if you checked the power supply...which is always the first thing to check. Not only check if correct DC voltage, but also check AC ripple level. Another thing: Have the proper ground mods been done to this game?

You are correct, I haven't checked, and will need to do so. (I'm not a Gottlieb guy, so this is new territory for me.)
The ground mod has NOT been done, either. (In either game.)

#4 8 months ago
Quoted from Coyote:

If I disconnect the lamps, it *seems* as if the game stops missing switches. (However, this is so random, it may be a red herring.)

Don't forget the relationship of the lamps and switches:

Shared Strobe between Lamp and Switch Matrix.
Because the Lamp Matrix and the Switch Matrix share the same twelve strobe lines, a shorted lamp socket can cause havoc with the Switch matrix. Also the organic flux used on Gottlieb lamp sockets can cause lamp shorts, which in turn can cause strange and mysterious switch matrix problems.

Therefore if you're having strange switch matrix issues, it's always best to remove connector A3J4 from the driver board, and re-check the switch issues. Removing connector A3J4 disconnects the lamp matrix, so on the playfield it can't influence the switch matrix.

#5 8 months ago
Quoted from wayout440:

Don't forget the relationship of the lamps and switches:
Shared Strobe between Lamp and Switch Matrix.
Because the Lamp Matrix and the Switch Matrix share the same twelve strobe lines, a shorted lamp socket can cause havoc with the Switch matrix. Also the organic flux used on Gottlieb lamp sockets can cause lamp shorts, which in turn can cause strange and mysterious switch matrix problems.
Therefore if you're having strange switch matrix issues, it's always best to remove connector A3J4 from the driver board, and re-check the switch issues. Removing connector A3J4 disconnects the lamp matrix, so on the playfield it can't influence the switch matrix.

Yup! Did check that -

Quoted from Coyote:

If I disconnect the lamps, it *seems* as if the game stops missing switches. (However, this is so random, it may be a red herring.)

But, it's not a rock-solid test, since the 'missing switch' happens to infrequently, that it's really hard to tell - after 'x' games and no switch misses.. was it because I t just normally didn't happen, or disconnecting the lamps actually 'fixed' it?
The interesting thing is that the flashers (coil driven) are running dim *as well*, and they don't 'brighten up' when I disconnect the lamp matrix from the driver board.

#6 8 months ago

Yeah, I'd recommend the ground mods before doing anything else. If the grounds are poor, then they "float" above 0V and can cause weird problems. For example, a lamp expecting to see about 6.5V. If the ground floats at 1V, then the lamp effectively "sees" only 5.5V, and glows dimmer. It's just one possibility. And also verify all those voltages are correct on the power supply. Yours is an odd problem that I have not heard of before...and unless both those MPU boards have the same problem, you've pretty much ruled those out IMO. You seem on the right track with the troubleshooting.

#7 8 months ago

Maybe a stupid remark…..did u measure the secondary voltages? Is your game maybe jumpered for 220-240V operation??

There should be a connector at the tramsformer panel with just jumper wires. Gottlieb delivered for each voltage a jumper with specific wire colors. Blue and green are for 220VAC 240VAC operation (correct me if my memory is failing in this). They used orange also if I am correct. You can compare it with your working game.

#8 8 months ago

Awesome, thanks guys.
I know the issue - now I need to figure out why..

The 20v bridges in both games are getting 17.5vac in.
The good game voltage drop between the DC terminals of the bridge is 22.2vdc (give or take).
The game that's acting up, the voltage drop between the DC terminals is 14.5vdc.

The 33000mfd cap (the large one) is different between the two games.
The bad game has a 33000mfd, 15vdc(!!) cap, while the good game has 33000mfd 35vdc cap (and looks original).

Bad cap? (Guessing since the voltage of the bad game's cap is UNDER what the secondary should be sending, that could be the issue..)

#9 8 months ago
Quoted from Coyote:

]
Bad cap? (Guessing since the voltage of the bad game's cap is UNDER what the secondary should be sending, that could be the issue..)

Compare the AC ripple of the caps to determine if the cap is bad. Or just replace it. The nominal voltage should be selected for a safety factor of about 2 - in other words, if a cap is expected to be presented with 20V, the working voltage desired is about 40V but 35 was chosen because it is more common. Even if cap is not the problem, overvoltage on the cap can shorten its lifespan.

#10 8 months ago

Yup, looks like cap is bad, or at least at fault cuz of overvoltage.

Good game reports 53mVAC on the 20v feed.
Bad game reports 7.6VAC on the 20v feed.

Will order a new cap, and give that a shot.

#11 8 months ago
Quoted from Coyote:

Yup, looks like cap is bad, or at least at fault cuz of overvoltage.
Good game reports 53mVAC on the 20v feed.
Bad game reports 7.6VAC on the 20v feed.
Will order a new cap, and give that a shot.

Good luck!

#12 7 months ago

Thanks again guys.

New cap arrived, I dropped it in. (Got a rather expensive one, at $25 a pop, that was 35v and screw-terminals.) Powered game up, and lamps were nice and bright - everything looked normal like the game next to it.

Got two small switching 5v power supplies for both games, will be installing them this weekend and going the ground mod.

#13 7 months ago

Why doing the groundmod in system 3 games? Gottlieb used decent connectors in system 3. Groundmod is not needed.

#14 7 months ago
Quoted from MarAlb:

Why doing the groundmod in system 3 games? Gottlieb used decent connectors in system 3. Groundmod is not needed.

It isn't the quality or otherwise of the connectors. They simply didn't wire some grounds in place.

This can cause all sorts of voltage errors because of some floating grounds.

The suggested mods tie all the grounds together as they should have been in the first place and prevent random things as well as damage to the electronics.

#15 7 months ago

The biggest reason to perform the mod is because the boards in the backbox are not mounted to a metal plate with conductive standoffs.

Full explanation detail in your Gottlieb repair bible:
http://www.pinrepair.com/sys3/#gnd

#16 7 months ago
Quoted from wayout440:

The biggest reason to perform the mod is because the boards in the backbox are not mounted to a metal plate with conductive standoffs.
Full explanation detail in your Gottlieb repair bible:
http://www.pinrepair.com/sys3/#gnd

I just noticed this for the first time last night. I knew plastic standoffs were used, but I always assumed there was ONE metal one for each board. Nope. Strange since they went out of their way to GROUND the foil-covered wood..

The pic is my new switching 5v supply to replace the old one, pretty happy how it turned out.

rDaIazg (resized).jpg
#17 7 months ago
Quoted from Homepin:

It isn't the quality or otherwise of the connectors. They simply didn't wire some grounds in place.
This can cause all sorts of voltage errors because of some floating grounds.
The suggested mods tie all the grounds together as they should have been in the first place and prevent random things as well as damage to the electronics.

Quoted from wayout440:

The biggest reason to perform the mod is because the boards in the backbox are not mounted to a metal plate with conductive standoffs.
Full explanation detail in your Gottlieb repair bible:
http://www.pinrepair.com/sys3/#gnd

I know the groundmod myths already and I just strongly disagree to perform them in sytem 3 games. We are running a >100 game collection, from which many Gottliebs, I am also a volunteer in a pinball repairshop 1 day in a week. I never saw a system 3 game having problems with grounds. System 80 games do and also those in which groundmods were already performed but in such a way they are causing more problems then solving them. But of course....everyone can work on their machines in the way they want. I do it my way (and don't follow the hurd….better to think by yourself from time to time as I learned as a technician/engineer).

#18 7 months ago
Quoted from MarAlb:

I know the groundmod myths already

Well, your free to agree or not, but your opinion does not change the design. Since System 3s were not designed with ground plane topology, the modification to a star topology was designed to overcome problems with poor grounds through the wiring. The background audio was reduced by more than half when I screwed that last lug into the transformer frame on my CBW.
I know it is only one game and one example, but I didn't design the mod, and it's been around longer than I have been in the hobby. I'm an audio electronics quality engineer by trade, and I believe the mod is an improvement. To each his own.

#19 7 months ago

Speaking as a electronics design engineer for high end satellite communications gear....

None of the SS pinball manufacturers had good grounding schemes, Gottlieb was the worst with their System 80.
Their model 3's improved as the 4.2mm connectors were a tremendously improved connector. Their grounding scheme still sucked even though the connectors were better.

Nothing beats a screw terminal for good grounding. Crimp terminal, heavy gauge wiring and ground screws can't be beat.
With 50/50 hind sight - would have been nice if all of the boards (regardless of manufacturer) had a ground screw connections and a proper grounding scheme (e.g. star ground). Terminals with screw connections for high current power as well - no more burned connectors on power supplies! But they went for the high profit/short life span design... and I sell tons of replacement power connectors as a result.

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