(Topic ID: 206320)

System 1 Rom and continuous scoring


By Sonora70

1 year ago



Topic Stats

  • 22 posts
  • 6 Pinsiders participating
  • Latest reply 1 year ago by CactusJack
  • No one calls this topic a favorite

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#1 1 year ago

Still trying to get the Close Encounters of the Third Kind worked out. Had everything rolling then the continuous scoring began. I believe it's primarily associated with the drop targets. I've cleaned, re-pinned, and adjusted the switches and connectors, completed the ground mods but still doing it. I have a new power supply board so I'm thinking my voltage is correct. I've read that it could be the game rom? If so, what is the best source for rom? Should I go the eprom route if that is the problem? If so, what's the source?

#2 1 year ago

Have you done a switch test to see what switch(es) are being activated?

#3 1 year ago
Quoted from ForceFlow:

Have you done a switch test to see what switch(es) are being activated?

Short answer is no. Not sure the switch test would tell me anything? The continuous scoring doesn't occur until the drop target switches are dropped. Doesn't seem to do it at any other contact. The drop target switches remain "connected" when they are dropped. They should only score once but they continue to score.

#4 1 year ago
Quoted from Sonora70:

Not sure the switch test would tell me anything?

It would tell you if a switch is closed when it shouldn't be.

After eliminating any potential physical issues with switches, then you would proceed to test for switch matrix issues.

#5 1 year ago

Started working with the pin again this morning. The continuous scoring is with the spinner and drop targets. It will not go into test mode either which is a new development. Could my new 7405 and 7404 chips be bad?

#6 1 year ago

When the test switch is pressed a new game starts

#7 1 year ago

I had a scoring issue that was fixed with a new socket for the ROM chip. I'd think if the ROM was bad it would not work at all.

#8 1 year ago
Quoted from ripple:

I had a scoring issue that was fixed with a new socket for the ROM chip. I'd think if the ROM was bad it would not work at all.

Thx for the tip. Will try and report back.

#9 1 year ago
Quoted from Sonora70:

When the test switch is pressed a new game starts

That makes me think you have a switch strobe (output) either shorted to ground or stuck low (bad IC).

Check start button blades and coin switches (especially the coin lock out wiskers).

If you have done the slam switch mod on the MPU, You can start a game and then unplug the edge connector that goes to the cabinet switches and see if the playfield behaves normally.

#10 1 year ago
Quoted from CactusJack:

That makes me think you have a switch strobe (output) either shorted to ground or stuck low (bad IC).
Check start button blades and coin switches (especially the coin lock out wiskers).
If you have done the slam switch mod on the MPU, You can start a game and then unplug the edge connector that goes to the cabinet switches and see if the playfield behaves normally.

Additionally, check the strips of diodes in the cabinet and on the underside of the playfield. Those are part of the switch matrix, and if one of those is shorted, then you will get odd behavior. Note that you can't replace those with 1N4004 or 1N4148 diodes, unfortunately--you'll have to use a 1N270 or CDSH-270 germanium diodes.

http://pinwiki.com/wiki/index.php?title=Gottlieb_System_1#Switch_Matrix

#11 1 year ago

Thanks for the tips, I'll take a look and do a follow up. Not sure what it means but all the switches that are causing the continuous scoring as well as the test switch are on the same row on the matrix.

#12 1 year ago

It means that the "strobe" they all share in common is stuck low. Could be a ground short or a bad Output IC.

Similar discussion here including snippet of the SW matrix showing the 7404 strobe drives.

https://pinside.com/pinball/forum/topic/system-1-driver-board

#13 1 year ago
Quoted from ForceFlow:

Additionally, check the strips of diodes in the cabinet and on the underside of the playfield. Those are part of the switch matrix, and if one of those is shorted, then you will get odd behavior. Note that you can't replace those with 1N4004 or 1N4148 diodes, unfortunately--you'll have to use a 1N270 or CDSH-270 germanium diodes.

I found plenty of choices on Ebay, I just ordered some for my Joker Poker

ebay.com link » Bkc International 3658amo302701 1n270 Germanium Glass Diodes Lot 100

#14 1 year ago
Quoted from ckcsm:

I found plenty of choices on Ebay, I just ordered some for my Joker Poker
ebay.com link » Bkc International 3658amo302701 1n270 Germanium Glass Diodes Lot 100

I don't think I'd ever use that many. Out of all the sys1 games I've worked on, I've probably used less than 10 of those diodes.

#15 1 year ago
Quoted from CactusJack:

It means that the "strobe" they all share in common is stuck low. Could be a ground short or a bad Output IC.
Similar discussion here including snippet of the SW matrix showing the 7404 strobe drives.
https://pinside.com/pinball/forum/topic/system-1-driver-board

I'll take a look at the switches on the coin door tomorrow and plug in a new 7404 chip as well.
I just replaced it, but maybe faulty? Glad I put sockets on the board.

#16 1 year ago
Quoted from Sonora70:

I'll take a look at the switches on the coin door tomorrow and plug in a new 7404 chip as well.
I just replaced it, but maybe faulty? Glad I put sockets on the board.

Do you have a chip tester? That takes out some of the guesswork when it comes to 7400 series chips.

ebay.com link

#17 1 year ago
Quoted from ForceFlow:

Do you have a chip tester? That takes out some of the guesswork when it comes to 7400 series chips.
ebay.com link

I don't. I'm just beginning to venture into the solid state pinball. Not sure what equipment I need.

#18 1 year ago

But if they all share the same switch return line, then it may be a bad 7405 or associated components.

Again, if you haven't done the slam switch mod jumper, you can jumper a cap on the MPU board with an alligator clip jumper. This way, you can unplug both the playfield matrix (J7) and the lower cabinet matrix (J6) to see if the issue is coming from wiring.

#19 1 year ago

Is it a brand new modern power supply, or one transplanted from another machine? We had the same problem with Solar Ride, with spurious bonus increases and acting like the entire bank of drop targets had been dropped, and the switch test was showing switches that didn't actually physically exist in the switch matrix being triggered. It turned out to be the power supply (which came from another System 1) was no longer giving good voltage. The machine finally just started locking up. I replaced the power supply with a new build from Gulf Pinball via Marco (I decided I didn't want to fiddle with the old ones anymore), and it's been (almost) rock solid since. I think I've had two instances of "four targets dropped, machine thinks all five are", and I've got capacitors to replace the MPU power filter capacitors and replacement 7405 chips now on hand in case it does that again.

#20 1 year ago

Problem solved....... I replaced the new 7404 chip I put in a couple days ago. It is now working correctly. I assume the chip went bad or was defective? At any rate, I played several games today and it worked well.

Thanks much for all the tips and help. Some good ideas to help isolate issues.

#21 1 year ago
Quoted from LynnInDenver:

Is it a brand new modern power supply, or one transplanted from another machine? We had the same problem with Solar Ride, with spurious bonus increases and acting like the entire bank of drop targets had been dropped, and the switch test was showing switches that didn't actually physically exist in the switch matrix being triggered. It turned out to be the power supply (which came from another System 1) was no longer giving good voltage. The machine finally just started locking up. I replaced the power supply with a new build from Gulf Pinball via Marco (I decided I didn't want to fiddle with the old ones anymore), and it's been (almost) rock solid since. I think I've had two instances of "four targets dropped, machine thinks all five are", and I've got capacitors to replace the MPU power filter capacitors and replacement 7405 chips now on hand in case it does that again.

I actually have a new rottendog power supply.

Quoted from CactusJack:

But if they all share the same switch return line, then it may be a bad 7405 or associated components.
Again, if you haven't done the slam switch mod jumper, you can jumper a cap on the MPU board with an alligator clip jumper. This way, you can unplug both the playfield matrix (J7) and the lower cabinet matrix (J6) to see if the issue is coming from wiring.

I looked for this mod some today and couldn't find a clear description of it.......I've read/seen it but just couldn't get my hands on it when I needed it.

#22 1 year ago

Glad you got it working without having to pay for a new MPU board. Switch matrix is one of the most common "damage" areas of both Gottlieb System 1 and System 80 due to the fact that the playfield has higher voltages present than the ICs can handle and when people get their hands in there and start fooling around with the power on (not saying you did!), its very easy to zap something.

Clay has a good write up on the slam circuit and mod. But personally, I don't like to permanently defeat the slam circuit on my games as its nice to have the slam switch present to exit out of test or restart a game without having to cycle power. But it is always good to know the location of that cap (missing in his photo) so you can install an alligator clip jumper for troubleshooting purposes.

http://www.pinrepair.com/sys1/#slam

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