Author Topic: stern pinball Logic repair  (Read 1944 times)

0 Members and 1 Guest are viewing this topic.

Offline salviador

  • Regular Contributor
  • *
  • Posts: 60
  • Country: it
    • https://www.youtube.com/user/mancio92M
stern pinball Logic repair
« on: May 22, 2017, 10:28:41 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, 10:30:13 pm by salviador »
 

Offline Andy Watson

  • Super Contributor
  • ***
  • Posts: 1677
Re: stern pinball Logic repair
« Reply #1 on: May 22, 2017, 10:42:25 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: 60
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #2 on: May 22, 2017, 11:24:15 pm »
Thank you Andy!

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

Offline Andy Watson

  • Super Contributor
  • ***
  • Posts: 1677
Re: stern pinball Logic repair
« Reply #3 on: May 22, 2017, 11:48:32 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 23, 2017, 12:36:45 am »
so what board is it?
got any photo's?

most problems like this are caused by bad chip sockets.
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 60
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #5 on: May 23, 2017, 01:05:06 am »
send photo
 

Offline Pinkus

  • Frequent Contributor
  • **
  • Posts: 588
Re: stern pinball Logic repair
« Reply #6 on: May 23, 2017, 01:47:16 am »
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: 60
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #7 on: May 23, 2017, 03:09:02 am »
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: 2681
  • Country: gb
Re: stern pinball Logic repair
« Reply #8 on: May 23, 2017, 05:17:54 am »
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
 

Online DaJMasta

  • Super Contributor
  • ***
  • Posts: 1427
  • Country: us
    • medpants.com
Re: stern pinball Logic repair
« Reply #9 on: May 23, 2017, 05:54:57 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.
 

Offline edavid

  • Super Contributor
  • ***
  • Posts: 2705
  • Country: us
Re: stern pinball Logic repair
« Reply #10 on: May 23, 2017, 05:59:33 am »
Did you try swapping the CPU?

 

Offline Pinkus

  • Frequent Contributor
  • **
  • Posts: 588
Re: stern pinball Logic repair
« Reply #11 on: May 23, 2017, 06:37:35 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.
that is probably the best way to proceed
 

Offline salviador

  • Regular Contributor
  • *
  • Posts: 60
  • Country: it
    • https://www.youtube.com/user/mancio92M
Re: stern pinball Logic repair
« Reply #12 on: May 23, 2017, 07:40:57 pm »
I changed 80% logic, worked for 10 minutes and then as before  :palm:
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf