(Topic ID: 118913)

Gorgar intermittent 2 player start issue


By Jabbles180

5 years ago



Topic Stats

  • 25 posts
  • 14 Pinsiders participating
  • Latest reply 10 months ago by KingHebes
  • Topic is favorited by 4 Pinsiders

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#1 5 years ago

Hello pinside.

I have a gorgar here that has me stumped.

Every so often when I go to start a one player game it instead starts a two player game. This is an intermittent problem.

So far ive gone into the switch edge test to see if maybe the back stroke of the leaf switch was causing a second signal. That checked out ok. I cant get the switch to record a double hit.

I changed the diode on the switch thinking maybe some transient voltage was backfeeding somehow causing the double hit. That didnt help.

I then changed out the switch with a tested working switch and a new diode yet again. That seemed to fix it. But now after testing over 50 games its back.

Ive traced wires looking for breaks or any other visual clues that would point to the wiring. Everything looks good there.

I did a fatory reset to make sure it wasnt some setting.

Ive switched out boards to known working boards. Nothing changed.

At this point im pretty sure I can mark off board issues.
I feel I should be able to mark off the switch and diode.
Cant find an issue with the wiring.

Any advise?

#2 5 years ago

Morning bump

#3 5 years ago

Anyone?

#4 5 years ago

Weekend crowd, can you help out?

#5 5 years ago

Does the second player start coincide with the ball being sent into the shooter lane? If so, this really seems to be some kind of weird System 6/6A issue. This is at least the third post I've seen about the issue, one that I have myself with a Blackout, and another has it with an Alien Poker. I've mostly ignored it and just played the two player game when it happens. I know, that doesn't help. I've looked at the schematics and haven't seen any obvious common element that could cause it.

Here's another example:

https://pinside.com/pinball/forum/topic/alien-poker-oddity

#6 5 years ago

Ill have to check if it coincides with the ball being kicked out the trough or in the shooter lane.

I can point out that the game has the same problem with a replacement rottendog board and the original board. So im definitely leaning toward the issue coming from something other than the boards.

Ill have to dig further but Im placing a bet on a backfeed from something down the line or some kind of transient voltage, which may include the grounding circuitry.

#7 5 years ago

Our Gorgar did this, Time Warp, Scorpion, and a couple other system 6s have done this. We have checked and changed and rechecked switches, diodes, connectors etc. it will go away for awhile and then just do it again...as Neurkinetik said I think it is just a system 6 thing. No reason that we have ever found, just a glitch in some system 6s and 6As. We have some system 6s and 6As that have never done it. It seems to be just a system 6 or 6A thing no system 7s we have had have ever had this issue...

Phoebe

#8 5 years ago

The thing that gets me is what makes a sytem 6 a system 6 is the boards. So saying its a system 6 problem is logically saying its a board problem. Yet putting in a set of known working boards from another system 6 game that doesnt have this issue yields no change. Gorgar with the known working boards still has the issue.

Something is different making a percentage of system 6 games do this. So now, is it down the line on wiring and components or could it be an issue with roms?

Roms seem to be a out of the equation as the rottendog board uses its own rom chip seperate from the chips in my original boards.

This is why I believe it must be down the line from the boards.

Sadly, the only answer I seem to get from scouring the internet is, there is no fix. Just live with it. Or, everything logically that can be done has been done with no solution. That concept is rrally hard for me to grasp.

#9 5 years ago

If the boards are not the issue, then the first thing I'd look at is grounding, and/or power supply.

#10 5 years ago

Neurokinetik, ive been screwing around with it for the last hour or so again.

It definitely puts in the second player when the ball kicks to the trough.

This adds a couple components into the mix. The trough switch, the trough kicker solnoid, or continuity through the metallic assemblies between these parts.

Ill definitely be spending more time on this in the next week or so.

#11 5 years ago

Well this may be premature, but im going to call this solved.

I did quite a bit. I isolated all the metal assemblies around the trough so there was absolutly no continuity between them. Tested, issue is still there.

Then I changed the diode on the trough solnoid and cleaned up some ground strands. This seemed to be the problem. Im thinking it was the diode at the trough solenoid to be honest. Cant exactly tell you the logic behind it though.

So far im at 100 games played without issue. This is over 2 sessions. Played some games. Did a bunch of switch hit drain games. Also a bunch of turn the game off start a game runs. Since the first couple games seemed to be when the issue popped up the most.

Ill reply in the next couple days as I stress test the game to see if it comes back.

2 weeks later
#12 5 years ago
Quoted from Jabbles180:

Well this may be premature, but im going to call this solved.
I did quite a bit. I isolated all the metal assemblies around the trough so there was absolutly no continuity between them. Tested, issue is still there.
Then I changed the diode on the trough solnoid and cleaned up some ground strands. This seemed to be the problem. Im thinking it was the diode at the trough solenoid to be honest. Cant exactly tell you the logic behind it though.
So far im at 100 games played without issue. This is over 2 sessions. Played some games. Did a bunch of switch hit drain games. Also a bunch of turn the game off start a game runs. Since the first couple games seemed to be when the issue popped up the most.
Ill reply in the next couple days as I stress test the game to see if it comes back.

I'm 100 games in, I think you solved it, well done.
-mof

4 years later
#13 11 months ago

My gorgar does this and a friends flash does this. Can you guys confirm the issue still Hasn't come back? mof jabbles180

#14 11 months ago

Sounds more like the start switch isn't debounced in the code so occasionally it will register as two presses instead of one.

#15 11 months ago

Had TWO blackouts that did this exact same thing. Never did find the cause.

#16 11 months ago

Interesting my Stellar Wars does this every once in a while and mine happens to be one with system 6 board set.

#17 11 months ago

My Gorgar is at a friend's house permanently, so I have no idea about weird behavior like that, afaik it went away.
-mof

#18 11 months ago
Quoted from KingHebes:

My gorgar does this and a friends flash does this. Can you guys confirm the issue still Hasn't come back? mof jabbles180

Caused by a dirty start switch contact is occasionally opening and closing to put a second request in with one press.
After the contacts are cleaned it goes away.
To simulate this problem rapidly press start twice on a System 6 and the Ram will record the second push and apply it.

#19 11 months ago

Agree, dirty start switch contacts and poor or non-existent de-bounce code.

Clean the contacts by pulling paper through while gently pressing the contacts together. Then gap the contacts close together and tight against the start switch plunger. Works every time.

#20 11 months ago
Quoted from PINTEC:

Caused by a dirty start switch contact is occasionally opening and closing to put a second request in with one press.
After the contacts are cleaned it goes away.
To simulate this problem rapidly press start twice on a System 6 and the Ram will record the second push and apply it.

Cleaned the contact. Works perfect now. No double starts anymore! Thanks.

2 weeks later
#21 11 months ago

Ensure there is a ground lug on your power cord. Missing this causes two player starts.

#22 11 months ago
Quoted from Xenon75:

Sounds more like the start switch isn't debounced in the code so occasionally it will register as two presses instead of one.

This is actually the correct answer. It was always a problem from day 1 with these games - the way the williams switch matrix works in system 6 is the same way the bally/stern switch matrix is read for the fast react switches (slings and pops) - when it sees 2 closures in a row, it adds the switch to a queue. ("normal" switches on bally/stern need 3 in a row to be valid, and only activate once until it sees the switch open... this is why you can't add a switch matrix capacitor to williams switches to improve response, it will just keep scoring after the first activation).

Boardsets, dirty switches, diodes on coils, etc. are all red herrings. Yes, it will work correctly for a while, but eventually, it will come back, because leaf switches bounce. Someone with a heavy hand on the start button will get this a lot, one start on the push in, one start on the pull out.

The correct way to get this fixed is to add a small routine in the gamerom to the credit switch that turns off switch scanning for a short time - they already do this for some other switches on the PF (the outhole, and usually drop target switches on the reset stroke) - they could have added it to the credit switch easily. Probably didn't come up in their testing though.

Good software design takes into account [natural] deficiencies in hardware.

In this case you can minimize the double hits by widening the gap in the switch as much as you can, but it will still happen occasionally.

Oddly, in most cases when you are setting options in the adjustments you will NOT overshoot as you'd expect with the switch double hitting, because it is properly debounced in software in that case - there is a built in delay everytime you press/hold the button, and it reads it differently - it polls the closure instead of just reacting to a queue. It's not practical to scan an entire switch matrix that way though, it would be too slow.

#23 11 months ago

For anyone who wants to really get to the root of this problem you can use the "bounce" test ROM in this package: http://pincoder.ca

It will easily show you if any of your switches are in fact double bouncing. I wrote this ROM because I have exactly the same issue with my gorgar. and yes, it's occasional.

When I run the bounce test on mine, the switches register exactly as they should, so for my gorgar, the boards are fine, as are the switches and wiring. I can only assume the problem is in how Williams wrote the GREEN ROMs.

Having said that, if you run the bounce test ROM and it shows actual bouncing on any switch then you should start with the switches and make sure they have the correct gap etc. Then look at wiring. If all is well there then the problem is likely a bad PIA chip. The documentation for the each of the test ROMS will help you find the problem.

There are many other valuable test ROMs you can use to check the rest of your machine. Download a copy and take a look at the docs for each test. They're very easy to use!

#24 11 months ago

Seems to be an issue on System 6 games with green flipper ROMS. Have fixed a couple by replacing the paper between the contacts on start switch.

2 weeks later
#25 10 months ago

My gorgar did this but i just cleaned the contact on the start button with isopropyl alcohol. Now i never get double starts unless the start button is actually pressed twice.

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