(Topic ID: 293352)

Gottlieb Mars System 80 Problems- Wumpf CPU and Lighting

By Knxwledge

5 months ago


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  • 22 posts
  • 5 Pinsiders participating
  • Latest reply 27 days ago by Stemmy
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#1 5 months ago

Having a couple problems getting my Mars running. One is with the new Wumpf CPU I bought and one is with the lamps on the PF.

I bought a new Ni-Wumpf CPU off Pinside, set it up to work with Mars, but when it tries to start a game it says "Tilt, tilt, tilt", the PF goes dark and it says "Bad one" on the display. I emailed Ni-Wumpf about this, they told me that "Bad one" means something is wrong in association with the slam switch. In switch test, the CPU tells me to clean switch 77 but according to the manual there is no switch 77. Haven't heard anything back from them about this. FB video link of how the game is behaving: https://www.facebook.com/groups/pinballrepair/permalink/4110867172268792/?sfnsn=mo

My other issue is with the lights on the PF. I was initially having problems with lamps being stuck on or not lighting. I've checked all transistors and chips on the original driver board with my multimeter. I then implemented the thunk cure via this method (https://www.flippers.com/gott-system80.html#thunk), but botched it. I ended up cutting away the legs you were only supposed to lift. I was able to (I think) rectify it by soldering cap legs in place of the chip legs. After this implementation of the thunk cure the problems with lighting got worse, so I got rid of it. Now F2 blows semi-regularly and I'm not sure what's causing it. Back to having some lights stuck on, which seem to be random and not associated with just one particular chip.

I've changed the filter cap, did ground mods, replaced BRs, rebuilt/repinned the power supply, repinned the interconnect harness, and repinned a couple connectors on the MPU (I can't remember which)

As always, any help appreciated.

#2 5 months ago

It's one of the missing switches. http://www.papinball.com/tips/sys80_missing_switches.html

Does the mpu have an option to turn off or disable the slam tilt?

How is the playfield and switch connector? The new boards are great but the connectors can still be a cause of problems if they need to be redone.

#3 5 months ago
Quoted from Cheddar:

It's one of the missing switches. http://www.papinball.com/tips/sys80_missing_switches.html
Does the mpu have an option to turn off or disable the slam tilt?
How is the playfield and switch connector? The new boards are great but the connectors can still be a cause of problems if they need to be redone.

I don't see #77 listed in that list of missing switches.
I'm not sure if this is the default option (I don't see why it wouldn't be), but the MPU is supposed to ignore stuck slam switches:

Slam switch agnostic - stuck switches are ignored

(http://www.ni-wumpf.com/System80CPU.html)

As for the playfield and switch connector, I will have to double check which ones those are, but looking at photos online it looks like the ones I repinned on the MPU are J4 and J5. I will double check when I'm back in the garage.

Something I realized is that I have the coin door slam switch wires snipped. They aren't shorted to ground or anything, but maybe it being disconnected is the issue? I'm assuming that's not the problem but I could try reconnecting them.

#4 5 months ago
Quoted from Knxwledge:

I don't see #77 listed in that list of missing switches.
Something I realized is that I have the coin door slam switch wires snipped. They aren't shorted to ground or anything, but maybe it being disconnected is the issue? I'm assuming that's not the problem but I could try reconnecting them.

The slam switch is normally closed so you need to find those coin door wires and connect them

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#5 5 months ago
Quoted from Cheddar:

The slam switch is normally closed so you need to find those coin door wires and connect them
[quoted image]

Oh yeah yknow, that probably is it, considering it says it ignores stuck switches, not the switch entirely. I will connect them and report back. I assumed it would work in the same way as the Bally SS games, but Bally slam switches are normally open.

#6 5 months ago

I reconnected the coin door switch, pushed the tilt switch together under the PF, and it didnt fix it.

Also, since I hadnt worked on this machine in a while I forgot Ive got coils locking on on startup as well that I disconnected for testing purposes. The ball gate, ramp lift and right launch lane coils are the culprits.

I repinned J4 (the interconnect harness), J5 and J6 on the MPU

I was incorrect on which fuse is blowing. F3 which is an 8a Slow associated with lamps is blowing. I have been using 7a slows because theyre all I have but they weren't blowing before I undid the botched thunk cure

Edit: I got the game to start properly. I soldered the 2 wires of the coin door slam switch together and it's now starting properly. Why it can't just say "Slam" on the display is beyond me... how are you supposed to figure out that "Bad one" means slam? Lol
For any future readers who may have this problem, switch 77 is in fact the coin door slam switch

#7 5 months ago

Pics of my driver board, maybe someone here with a keen eye can spot a problem. Was thinking of trying to repin the individual pins of J3 on the driver board which are giving me issues.

You can see how I repaired the chip legs with cap leads. Everything ohms out how it's supposed to, all those pin 1s are connected to the 5v line.

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#8 5 months ago

I tried checking diodes, repinning individual pins on the driver board which are associated with coils giving me problems, cleaning fuse holders, ensuring solder connections are good, and I've not made any progress. I also tried leaving the game on for a while with the coils/lamps disconnected to see if any components on the driver board got hot, and I didn't notice anything.

The ball release coil seems to have stopped acting up, and I don't know that I did anything to fix it. The right bank coil seems to go off and on randomly when the game is on. It doesn't consistently lock on, it'll lock on for a while, then stop, then lock back on, etc.

I've tried searching for similar issues with System 80s but have come up empty-handed.

#9 5 months ago

How is your interconnect cable? Bad connections on this make all sorts of madness happen.

I have found it's best to test these driver boards on a bench with a DMM in diode test.

For the transistors: https://pinwiki.com/wiki/index.php?title=General#Testing_a_Transistor.2C_Silicon_Controlled_Rectifier_.28SCR.29_or_Field_Effect_Transistor_.28FET.29

I have noticed that sometimes the gottlieb transistors all appear to test bad. In this case I try the other tests on them until I get expected results and use that test on that type of transistor. Note: I think there are 4 models of transistor on this board. Once you find a good test for one model test all of them. I find it easier to test from the back and I put a sharpie dot next to the ones that test bad. You can remove the dot with alcohol later.

Test the chips like this:
in diode test connect the red lead to ground of the board.
probe each leg of the ic with the black leg. Ground should be a short and the 5v led will be ~.3
each other leg should be between .4-.6 (although if you are getting consistent numbers on your ics go with that).
On a sys 80 driver almost all the ics will test out this way except Z13 where pins 11 and 13 are tied to pin 7 and should read the same as it.

You are more likely to have shorted or open pins than out of range values but make note of the ones you do find. It is far more likely transistors are bas than the ics.

I found it: https://www.pinwiki.com/wiki/index.php?title=General#Testing_an_integrated_circuit

#10 5 months ago
Quoted from Cheddar:

How is your interconnect cable? Bad connections on this make all sorts of madness happen.
I have found it's best to test these driver boards on a bench with a DMM in diode test.
For the transistors: https://pinwiki.com/wiki/index.php?title=General#Testing_a_Transistor.2C_Silicon_Controlled_Rectifier_.28SCR.29_or_Field_Effect_Transistor_.28FET.29
I have noticed that sometimes the gottlieb transistors all appear to test bad. In this case I try the other tests on them until I get expected results and use that test on that type of transistor. Note: I think there are 4 models of transistor on this board. Once you find a good test for one model test all of them. I find it easier to test from the back and I put a sharpie dot next to the ones that test bad. You can remove the dot with alcohol later.
Test the chips like this:
in diode test connect the red lead to ground of the board.
probe each leg of the ic with the black leg. Ground should be a short and the 5v led will be ~.3
each other leg should be between .4-.6 (although if you are getting consistent numbers on your ics go with that).
On a sys 80 driver almost all the ics will test out this way except Z13 where pins 11 and 13 are tied to pin 7 and should read the same as it.
You are more likely to have shorted or open pins than out of range values but make note of the ones you do find. It is far more likely transistors are bas than the ics.
I found it: https://www.pinwiki.com/wiki/index.php?title=General#Testing_an_integrated_circuit

I did repin the entire interconnect harness. When I was working on this a few months ago I remember testing all the diodes and ICs like the ways you described but I'll do it again and see if I missed something.

1 week later
#11 4 months ago

I bought a brand new Wumpf driver board, repinned most of the driver board pins (I ran out of the pins required for J3 so I didnt get to do the entire thing but I did every other pin on all connectors), and nothing has changed. The Wumpf driver board uses LEDs to indicate open or faulty circuit, and the only which ones are lit are the ones which the game does not utilize. This is confirmed normal operation in the manual of the driver board. I do notice that when the game is in attract the F3 lamp fuse gets warm to the touch, and when in test it gets so hot I cant touch it. Is that normal?

I did notice some burned wires at J5 of the MPU but I doubt that has anything to do with it.

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#12 4 months ago

Hot fuses or burned wires are not normal, too much current or voltage, maybe not enough to break.

Something is pushing either too much current or voltage, short somewhere or broken wire.

#13 4 months ago
Quoted from Bmad21:

Hot fuses are not normal, too much current or voltage, maybe not enough to break.
Something is pushing too much current or voltage, short somewhere or broken wire.

My 8v at my power supply when the game is in attract is 8.6v. The 8v is fed from the 12v and the 12v is also about 12.6v.

#14 4 months ago

I spoke with my dad on the topic (did not lay everything out but gave him enough info to go on) and he says that you are drawing too many amps.

He says that something is drawing to manny amps

I think you have a short somewhere.

Check physical board for any soder splashes or bridged traces.

#15 4 months ago
Quoted from Bmad21:

I spoke with my dad on the topic (did not lay everything out but gave him enough info to go on) and he says that you are drawing too many amps.
He says that something is drawing to manny amps
I think you have a short somewhere.
Check physical board for any soder splashes or bridged traces.

About 12 lamps are stuck on at all times. Ive visually inspected the underside of the PF multiple times, repinned the connectors going to the driver board, and put a new replacement driver board in. There seems to be no rhyme or reason to which lamps are stuck on.

They are 4x, 2nd right and center drop target, 1000, 5000 and 9000 bonus, bottom left pop bumper, left extra ball rollover. The M at the top of the playfield never lights.

The 6v line which connects all sockets is giving me 5.8v when game is in attract

#16 4 months ago
Quoted from Knxwledge:

About 12 lamps are stuck on at all times. Ive visually inspected the underside of the PF multiple times, repinned the connectors going to the driver board, and put a new replacement driver board in. There seems to be no rhyme or reason to which lamps are stuck on.
They are 4x, 2nd right and center drop target, 1000, 5000 and 9000 bonus, bottom left pop bumper, left extra ball rollover. The M at the top of the playfield never lights.
The 6v line which connects all sockets is giving me 5.8v when game is in attract

Did you buy the driver new or second hand? Check the signals coming from each of the 74175s or equivalent on the driver board.

Those chips might of gone bad.

#17 4 months ago

To me - those burned wires looked like surface burns on the wire. Multiple wires all in the same vicinity. Maybe at one time that bundle was routed under driver board and was in contact with a light bulb?

#18 4 months ago
Quoted from Bmad21:

Did you buy the driver new or second hand? Check the signals coming from each of the 74175s or equivalent on the driver board.
Those chips might of gone bad.

I have the same problem between the old driver board and the new one, so that can't be it. Someone on Facebook helped me out and showed me that the lights that are exhibiting issues are mostly tied to the first data line in the interconnect harness between the MPU and driver board. I'm going to doublecheck my work in repinning it.

Quoted from G-P-E:

To me - those burned wires looked like surface burns on the wire. Multiple wires all in the same vicinity. Maybe at one time that bundle was routed under driver board and was in contact with a light bulb?

Yeah I think you're right. They don't feel particularly brittle, and it isn't burned near the end of the wire at the connector so I think it's just surface burns. Regardless those wires are unrelated to the lamps and coils so I don't think it's causing any issues.

#19 4 months ago

This has been solved thanks to a gentleman on Facebook helping me out. Turns out I put a wire in the wrong hole when recrimping the interconnect harness. The first data line wasn't getting to the driver board, and it was leaving the lamps and coils in an unknown/non-reset state due to how the board was engineered.

3 months later
#20 28 days ago
Quoted from Knxwledge:

This has been solved thanks to a gentleman on Facebook helping me out. Turns out I put a wire in the wrong hole when recrimping the interconnect harness. The first data line wasn't getting to the driver board, and it was leaving the lamps and coils in an unknown/non-reset state due to how the board was engineered.

Where did you get your parts for repinning your edge connectors? Thanks. And what parts did you get?

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