Image Map Image Map

Search:

Type: Posts; User: giobbi

Page 1 of 20 1 2 3 4

Search: Search took 0.04 seconds.

  1. Replies
    31
    Views
    1,282

    I give up for now. I can't get the rid of the...

    I give up for now. I can't get the rid of the reset circuit, and honestly it's just a spare board I have, so I don't need it for now... well, I will not need it if I can fix my 8032-SX that suddenly...
  2. Replies
    31
    Views
    1,282

    I understand... Even if I'm quite sure I...

    I understand...

    Even if I'm quite sure I didn't damage the PCB (I have a good unsoldering station and I take a lot of care doing that; at least I didn't damage any tracks), I will check every...
  3. Replies
    31
    Views
    1,282

    extracting UE15 and UD15 shouldn't cut the /RESET...

    extracting UE15 and UD15 shouldn't cut the /RESET line between 555 and the other chips?
  4. Replies
    31
    Views
    1,282

    I can't get the rid of the reset circuit, I don't...

    I can't get the rid of the reset circuit, I don't know why.

    The 555 gives strange results at multimeter and probe.

    Pin 6,7 and 3 pulses; pin 3 sometimes pulses, then stays high for a while,...
  5. Replies
    31
    Views
    1,282

    EDIT: I changed R24 that seemed bad (actually,...

    EDIT: I changed R24 that seemed bad (actually, after removed I tested it, and it seems ok...) and things get slightly better:

    UD16 pin 3 should be LOW. -- ok
    UE15 pin 1 should be LOW. -- ok
    UE15...
  6. Thread: 8032 CRT issue

    by giobbi
    Replies
    26
    Views
    1,428

    ...eventually I've discovered the floating image...

    ...eventually I've discovered the floating image on the screen only appears when the 8032 is closed and the CRT assy get closer to the transformer... so I believe it's some kind of noise from the...
  7. Replies
    31
    Views
    1,282

    Here the results... BTW I haven't a new...

    Here the results...

    BTW I haven't a new 74LS17 (UD15) so i replaced it with a 74LS07, should be a 100% replacement


    UD16 pins 6 and 7 - both should be close to 5V.-- 4,84v
    UD16 pin 3 should...
  8. Replies
    31
    Views
    1,282

    I digged more and I found there's something wrong...

    I digged more and I found there's something wrong in the reset circuit (at least, it seems wrong to me).

    I compared the good and the bad 8032s and I've seen UD16 (555) pins have a different state....
  9. Replies
    31
    Views
    1,282

    I compared the video lines between the good and...

    I compared the video lines between the good and the bad (I'm the ugly, LOL). I have HIGH at UD4 pin 13 (section 8: dot gen & even display) when I should have a pulse, like pins 1 and 2. I replaced...
  10. Replies
    31
    Views
    1,282

    I got a strange (at least, it seems strange to...

    I got a strange (at least, it seems strange to me) behaviour of the CRTC, some lines (22 to 33) that sometimes pulse and sometimes stays low or high.

    I tried to connect the board to the monitor:...
  11. Replies
    31
    Views
    1,282

    aaaah, got it now!!! :) Well, I'm running out...

    aaaah, got it now!!! :)

    Well, I'm running out of idea, I don't know what to check now... lack of knowledge :(
    I will try to check the lines and post the result here, maybe you guys will discover...
  12. Replies
    58
    Views
    7,557

    Wonderful! It recalls memories of Battle Zone...

    Wonderful!
    It recalls memories of Battle Zone (arcade game), Alien and Blade Runner (those sci-fi computers -at least for that era :D )
  13. Replies
    3
    Views
    233

    I can confirm that; I have at least a couple of...

    I can confirm that; I have at least a couple of VICs with an eprom in place of the original Kernal. VIC roms seem to be quite weak and if the kernal is socketed, you should try to replace it.

    If...
  14. Replies
    31
    Views
    1,282

    Hi Dave. It should, I suppose, since it's a 32k...

    Hi Dave.
    It should, I suppose, since it's a 32k model.
    What should I check, first?
  15. Replies
    1
    Views
    200

    Thank you so much! --Giovi

    Thank you so much!
    --Giovi
  16. Replies
    31
    Views
    1,282

    I did some steps ahead (maybe...) I've found...

    I did some steps ahead (maybe...)

    I've found CAS1 (upper RAMs pin 15) is stuck high, while CAS0 pulses.

    I changed UD5 (74LS00), UE2 (74LS157) and UD13 (74LS244) with no results.

    Could it...
  17. Replies
    11
    Views
    896

    SOLVED I've discovered that the connector on...

    SOLVED

    I've discovered that the connector on the motherboard has the guide label in an opposite way, compared with a normal scsi cable, so the cable pin #1 was on the side of the pin #50 of the...
  18. Replies
    31
    Views
    1,282

    of course, I did it yet and found bad char rom...

    of course, I did it yet and found bad char rom and 1 of the three basic.

    Then I changed the 74154 and now they're warm while running.
  19. Replies
    11
    Views
    896

    Something went wrong, I don't know what, exactly....

    Something went wrong, I don't know what, exactly.

    I took the flat scsi cable from the external HDD box, I left the terminator pack connector at one side of the flat cable, put a...
  20. Replies
    31
    Views
    1,282

    The 6520s and the 6522 were ok, I tested them in...

    The 6520s and the 6522 were ok, I tested them in a working 8032. And -surprise- I inserted them back in place and the IRQ was ok (high). I can't say what happened and why I didn't work.

    ...
  21. Replies
    31
    Views
    1,282

    Thank you! I'm trying to fix the clock. I started...

    Thank you! I'm trying to fix the clock. I started from the 8032029-06.gif schematic, master timing. I've seen the pull up line (connected to pin 1 of the three 74177: UD3, UE6 and UE7) is HIGH. Is it...
  22. Thread: 8032 CRT issue

    by giobbi
    Replies
    26
    Views
    1,428

    Thank you Dave, I didn't think at that! I will do...

    Thank you Dave, I didn't think at that! I will do a try, of course, and I will tell you the result!
  23. Replies
    31
    Views
    1,282

    Please, explain me exactly what I should to...

    Please, explain me exactly what I should to check... unfortunately I don't know much about hardware, so you should not assume I'm understanding, LOL



    Well, I resumed all the 65xx ICs pin...
  24. Thread: 8032 CRT issue

    by giobbi
    Replies
    26
    Views
    1,428

    LOL I read in another thread about your...

    LOL

    I read in another thread about your pettester V.4, that works in the edit rom. Intrigued, I burned a 2716 eprom and tried it.

    surprisingly, the image was shifted on the left of the monitor,...
  25. Replies
    31
    Views
    1,282

    Good question... The crystal return a pulse on...

    Good question...
    The crystal return a pulse on probe, but the 555 pin 3 (I suppose it should pulse) start with a high state, and then goes to low.
Results 1 to 25 of 500
Page 1 of 20 1 2 3 4