Author Topic: stern pinball Logic repair  (Read 2405 times)

0 Members and 1 Guest are viewing this topic.

Offline salviador

  • Regular Contributor
  • *
  • Posts: 64
  • Country: it
    • https://www.youtube.com/user/mancio92M
stern pinball Logic repair
« on: May 22, 2017, 12:28:41 pm »
Hi, I'm fixing a stern pinball Of the 90's.
The pinball work but I have a problem, The cpu resets.
I connected my logic analyzer in the bus I noticed that the D2 is sometimes dirty, I've changed some 74 ttl logic but But I did not notice any improvements
Why the D2 databus is dirty?
« Last Edit: May 22, 2017, 12:30:13 pm by salviador »
 

Offline Andy Watson

  • Super Contributor
  • ***
  • Posts: 1744
Re: stern pinball Logic repair
« Reply #1 on: May 22, 2017, 12:42:25 pm »
Are the power supplies clean?
I have seen similar "random" logic changes due failing ground connections - due to poor vias and sometimes cold-joints. Check the power on the actual pins of the ICs.
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 64
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #2 on: May 22, 2017, 01:24:15 pm »
Thank you Andy!

My question is why only Data2 and not in other Data bit.
 

Offline Andy Watson

  • Super Contributor
  • ***
  • Posts: 1744
Re: stern pinball Logic repair
« Reply #3 on: May 22, 2017, 01:48:32 pm »
My question is why only Data2 and not in other Data bit.
I think my earlier answer is still valid. However, consider also: Your logic analyzer is telling you either 1 or 0 - it may be that the signal is at an indeterminate logic level - either because it is tri-state or because it is conflicting with an output that is not properly releasing the bus.
 

Offline stj

  • Super Contributor
  • ***
  • Posts: 2156
  • Country: gb
Re: stern pinball Logic repair
« Reply #4 on: May 22, 2017, 02:36:45 pm »
so what board is it?
got any photo's?

most problems like this are caused by bad chip sockets.
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 64
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #5 on: May 22, 2017, 03:05:06 pm »
send photo
 

Offline Pinkus

  • Frequent Contributor
  • **
  • Posts: 647
Re: stern pinball Logic repair
« Reply #6 on: May 22, 2017, 03:47:16 pm »
looks like you are using an Intronix Logicport. Did you try to raise or lower the logic threshold a bit? Maybe you are juuuust out of the valid range.
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 64
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #7 on: May 22, 2017, 05:09:02 pm »
looks like you are using an Intronix Logicport. Did you try to raise or lower the logic threshold a bit? Maybe you are juuuust out of the valid range.
Yer I try:
3.00v
2.50v
2.30v
2.00v

 

Offline grumpydoc

  • Super Contributor
  • ***
  • Posts: 2705
  • Country: gb
Re: stern pinball Logic repair
« Reply #8 on: May 22, 2017, 07:17:54 pm »
Some notes here http://www.pinballsupernova.com/images/Sega_Stern%20White%20Star%20Repair%20-%20PinWiki.pdf

I presume you have schematics

As ever, start with the PSU rails
 

Offline DaJMasta

  • Super Contributor
  • ***
  • Posts: 1880
  • Country: us
    • medpants.com
Re: stern pinball Logic repair
« Reply #9 on: May 22, 2017, 07:54:57 pm »
Do you have an oscilloscope as well?  Hook up a probe to the dirty line and a few to ones that seem to be good and see if there's a visual difference (or another working line and a rail or two).  Could tell you a lot about the source of the problem.
 

Online edavid

  • Super Contributor
  • ***
  • Posts: 2970
  • Country: us
Re: stern pinball Logic repair
« Reply #10 on: May 22, 2017, 07:59:33 pm »
Did you try swapping the CPU?

 

Offline Pinkus

  • Frequent Contributor
  • **
  • Posts: 647
Re: stern pinball Logic repair
« Reply #11 on: May 23, 2017, 08:37:35 am »
Do you have an oscilloscope as well?  Hook up a probe to the dirty line and a few to ones that seem to be good and see if there's a visual difference (or another working line and a rail or two).  Could tell you a lot about the source of the problem.
that is probably the best way to proceed
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 64
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #12 on: May 23, 2017, 09:40:57 am »
I changed 80% logic, worked for 10 minutes and then as before  :palm:
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf