Image Map Image Map
Page 3 of 38 FirstFirst 123456713 ... LastLast
Results 21 to 30 of 375

Thread: Commodore pet 3032 screen full of lines

  1. #21

    Default

    Quote Originally Posted by daver2 View Post
    ok thanks.

    So g11 pin 4 is bad.

    Can you check the following pins for pulsing with your logic probe please:

    G10 pin 6 (74ls00).
    G10 pin 8 (74ls00).

    G9 pins 8 and 9 (74ls74).

    E11 pins 7 and 9 (74ls165).

    Basically, i am working backwards on the schematic diagram until we find where things go from good to bad...

    Dave

    g10 pin 6=pulse
    g10 pin 8=pulse

    g9 pin 8=pulse
    g9 pin 9=pulse

    e11 pin 7=pulse
    e11 pin 9=pulse

  2. #22

    Default

    Quote Originally Posted by ilpaninaro View Post
    Sorry but i think that problem in this pet are the Rom....
    I tried to insert Pet tester in ud9 with only char rom inserted and i can see this double Attachment 55992Attachment 55993screen:
    That is good easter eagging but not good trouble shooting for reference to others. It would be better to finish trouble shooting with Dave for others looking at this thread. I suspect your right, blowing a set of ROMs will likely help. What do you mean by double screen?
    Dwight

  3. #23

    Default

    Quote Originally Posted by Dwight Elvey View Post
    That is good easter eagging but not good trouble shooting for reference to others. It would be better to finish trouble shooting with Dave for others looking at this thread. I suspect your right, blowing a set of ROMs will likely help. What do you mean by double screen?
    Dwight
    Double screen cause pettester show 2 alternates screen

  4. #24

    Default

    Quote Originally Posted by ilpaninaro View Post
    Double screen cause pettester show 2 alternates screen
    I guess I have to be a Pet person to understand. Nice to have an alternate screen.

  5. #25
    Join Date
    Jun 2012
    Location
    UK - Worcester
    Posts
    2,978

    Default

    >>> Double screen cause pettester show 2 alternates screen.

    No idea what you are talking about?

    Ok, with the PETTEST ROM in the kernal ROM socket you are getting video. Is that what we are saying? There is a small probability that the video screen had been erased completely but the code has crashed befor it has had a chance to display any meaningful characters on the screen. My test process would have identified that scenario if you had followed through with it...

    The 'first' screen indicates that page zero RAM is all bad/faulty (hence the b's). You need to explain further what the other screen of garbage is that you have shown. Does it alternate with the screen of b's? If so, at approximately what frequency?

    Dave

  6. #26

    Default

    Quote Originally Posted by daver2 View Post
    >>> Double screen cause pettester show 2 alternates screen.

    No idea what you are talking about?

    Ok, with the PETTEST ROM in the kernal ROM socket you are getting video. Is that what we are saying? There is a small probability that the video screen had been erased completely but the code has crashed befor it has had a chance to display any meaningful characters on the screen. My test process would have identified that scenario if you had followed through with it...

    The 'first' screen indicates that page zero RAM is all bad/faulty (hence the b's). You need to explain further what the other screen of garbage is that you have shown. Does it alternate with the screen of b's? If so, at approximately what frequency?

    Dave
    Hi Dave,yes the other screen it alternate with "b" screen every 2 secondos more or least...
    I ve also changed bad roms with new eprom and now i ve again black screen

  7. #27
    Join Date
    Jun 2012
    Location
    UK - Worcester
    Posts
    2,978

    Default

    So, we at least know that the video circuitry appears to work.

    Can you download my PETTEST code, burn it into a 2K EPROM, put it in place of the EDIT ROM and plug the kernal ROM in please. What do you see on the screen?

    You'll have to lookup my google drive reference on the VCFED Commodore thread though. It is currently version 4. This is an extended PETTEST than the one that lives in the kernal ROM socket and can test the video screen, page 0 and 1 of RAM, the keyboard and ROMs and a more extensive memory test of all of the RAM.

    EDIT: Here https://drive.google.com/drive/mobil...13&direction=a.

    Just a thought about your double screen. Is it possible that the character generator is faulty. I know you said that you have got the correct checksum, but if it is faulty you could get a screen of capital B's that get converted into random rubbish. I do, however, have a test for this scenario if your video RAM is socketed...

    Dave
    Last edited by daver2; September 13th, 2019 at 11:54 AM.

  8. #28

    Default

    Quote Originally Posted by daver2 View Post
    So, we at least know that the video circuitry appears to work.

    Can you download my PETTEST code, burn it into a 2K EPROM, put it in place of the EDIT ROM and plug the kernal ROM in please. What do you see on the screen?

    You'll have to lookup my google drive reference on the VCFED Commodore thread though. It is currently version 4. This is an extended PETTEST than the one that lives in the kernal ROM socket and can test the video screen, page 0 and 1 of RAM, the keyboard and ROMs and a more extensive memory test of all of the RAM.

    EDIT: Here https://drive.google.com/drive/mobil...13&direction=a.

    Just a thought about your double screen. Is it possible that the character generator is faulty. I know you said that you have got the correct checksum, but if it is faulty you could get a screen of capital B's that get converted into random rubbish. I do, however, have a test for this scenario if your video RAM is socketed...

    Dave
    Unfortunately now i don't have a 2716 eprom...can i burn your pettest on 2732 maybe?
    Thanks

  9. #29
    Join Date
    Feb 2009
    Location
    Southern California, USA
    Posts
    2,662

    Default

    Quote Originally Posted by ilpaninaro View Post
    Unfortunately now i don't have a 2716 eprom...can i burn your pettest on 2732 maybe?
    Thanks
    Yes, but burn the 2K code into the upper 2K address space from 0800 Hex to 0FFF Hex. In other words use a 0800 Hex block size (2048 decimal) and a transfer start address of 0800 Hex. Does that make sense to you?

  10. #30

    Default

    With bad zero page RAM, it is not likely to do much on the video out. Almost everything needs good page0 and some page1.
    Dwight

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •