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Fixing an old atari 130xe — Parallax Forums

Fixing an old atari 130xe

Invent-O-DocInvent-O-Doc Posts: 768
edited 2012-06-02 15:40 in General Discussion
Hi,

I've pulled all my old computers out of the chest and am setting them up. The Atari 800 is working and I suspect the 1040ST as well, but need to make a new monitor cable for that one.

My 130XE doesn't work, however. I get an empty orange screen, though the power LED works. I tested the power supply for voltage, which is correct. I also replaced the capacitors, some of which were bad - no difference. (3 of the caps were electrolytic appearing but non-polarized - never heard of those - I replaced two with electrolytics because they appeared to connect to ground and the third, which doesn't tested good so I put it back in).

Anyhow - what else is there to check? There is a 14.8MHz Crystal, do those go bad?? If nothing else is broken, then it is probably one of the chips and I'll have to give up.

Any thoughts?

Comments

  • kwinnkwinn Posts: 8,697
    edited 2012-06-01 22:44
    A few things to check. Scope required for most.
    - Check the crystal to see if it is oscillating. If not try replacing it. If that does not work try replacing the cpu chip. BTW crystals rarely die unless physically abused.
    - If the crystal oscillates see if the address lines are toggling.
    - If the address lines are toggling it may be that the eprom is bad or has erased over time (common with early eproms).
    - If there is any I/O activity (I/O chip select activity) the cpu and eproms are probably ok and the problem may be with the video.
  • davejamesdavejames Posts: 4,047
    edited 2012-06-01 23:19
    Any chips socketed? If so, remove and reseat.

    Great machine...wish I hadn't tossed all my Ataris (7) a couple years back. Reference books and all.
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2012-06-02 07:36
    Thanks. I'll check. The 130xe had a more advanced memory management system. All atari eight bits had a lot of custom ic chips. This model is all soldered unlike the 800 and early 800xls which used sockets. I suspect the rom. Most 8 bit models are cheap but the 130 is expensive to replace.
  • davejamesdavejames Posts: 4,047
    edited 2012-06-02 09:00
    The 130xe had a more advanced memory management system.

    ...yup! I hacked my 600XL to be "130xe compatable" with an additional 65K of memory. Also populated the empty video out circuity for composit video and using a real monitor.

    I was running ATARI Basic, ValStar Forth, and DeepBlueC.

    Man...I loved that little machine!
  • potatoheadpotatohead Posts: 10,261
    edited 2012-06-02 09:14
    Ask this on http://www.atariage.com

    Seriously. The tech oriented people there know these machines cold. You will fix it. I'm potatohead there too, if you need a friend to kick things off. :)
  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2012-06-02 11:11
    If you can't or don't want to fix it. I'll buy it from you or trade.
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2012-06-02 11:55
    Atariage was interesting. It seems that the RAM and Freddie chips go bad after time (especially the RAM).
  • kwinnkwinn Posts: 8,697
    edited 2012-06-02 14:21
    Atariage was interesting. It seems that the RAM and Freddie chips go bad after time (especially the RAM).

    If you have the documentation (schematics) it may be possible to use currently available ram chips to replace the original chips. I have done that quite often when repairing or refurbishing old equipment and would be happy to assist.

    Unfortunately that is not so easy to do with most custom chips. With those it's usually find an original or a clone chip.
  • ercoerco Posts: 20,259
    edited 2012-06-02 14:38
    Of course it may possible to nab a working unit off Ebay for a song (or less than the aggravation of unsoldering vintage ICs). Here's one currently at $10 with a keyboard issue that might get you up & running with just a board swap: http://www.ebay.com/itm/Atari-130XE-/160811593899?pt=US_Vintage_Computers_Mainframes&hash=item25711e30ab
  • davejamesdavejames Posts: 4,047
    edited 2012-06-02 15:40
    ...so, I'm wandering through Halted (the local surplus house) this morining scrounging for chassis and 2W C/C resistors when I see - in their boxes - an ATARI 520ST, two VIC-20s and a C-64.

    I think they wanted $75 for the ST.
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