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Thread: Looking for my old ADM-3A

  1. #1

    Default Looking for my old ADM-3A

    I used to have an ADM-3A Dumb Terminal... fixed it up, and made my own lower-case ROM from a 2716 EPROM and a lot of small wires.
    Sold it around 2005 or so, but can't remember who bought it.

    Anyway I'd like to buy it back if the current owner is out there and isn't using it
    Thanks
    Charles

  2. #2
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    Mar 2006
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    Salt Lake City, UT, USA
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    If you can't find the original, they show up on ebay fairly often.

  3. #3

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    Sure, there's a couple on there right now (at high prices though, especially when you factor in shipping).
    It's just one of those "shouldn't have sold it, now I want it back" things

  4. #4
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    Quote Originally Posted by DrCharles View Post
    Sure, there's a couple on there right now (at high prices though, especially when you factor in shipping)
    Recent completed sales for an ADM-3A on ebay:
    192827478293 $220.00 + $70
    323743149867 $158.50 + $73
    254170169347 $45.00 + $125
    332825368751 $299.95 + $90

    The guy who got one for $45 (+$125 shipping) got the best deal.

    You may consider these prices "high", but these terminals are sought after by many vintage collectors because they were commonly used in the late 70s/early 80s.

    I monitor terminal sales on ebay often and although I haven't been gathering records, the prices above are about average for what you should expect to pay for highly sought after serial terminals at this point (e.g. ADM-3A, VT100). If you are patient, you can find better prices (the $45.00 unit only had 1 bidder).

    Remember that just because these things were once ubiquitous and people weren't interested and therefore were cheap to buy, that isn't the case anymore.

    Sure, you used to trip over VT100s lined up on the curb outside some University surplus warehouse in the 90s, but those days are 20-30 years gone now.

    Most terminals were scrapped long ago. What's left is what's left.

  5. #5

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    Yep, I used them in the late 70's too!
    I'll bet the guy with the $165 "deal" got a busted one. Although (as an '80's EE who made my living designing and testing 8-bit embedded micros) I think I can fix one
    Apparently the values have indeed shot up in the last decade or so... I know shipping is very high these days, certainly when carefully double-boxed.
    Will have to consider if I want one that bad

    What would you recommend for a less expensive terminal to be used with my PDP-11/23+ running TSX+? I have a VT-220 as the console, a KSR43 printer, and a Silent 700 on one of my 16 timesharing lines for playing ADVENT without getting a headache...

    thanks
    Charles

  6. #6
    Join Date
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    From one of the photos in the auction, I infer that particular ADM-3A probably has a bad RAM chip in the screen memory and the epoxy holding the safety shield on the CRT has started to outgas, resulting in "CRT cataracts" or "CRT mold" (it's not mold). So yeah, that one needs some work.

    Generally speaking, the more recent the terminal the less expensive it will be.

    I don't know what your local area is like, but sometimes they can still be had for free if you "know a guy".

    For your setup, a VT220 is a good pick IMO, although I'm not a fan of the keyboard.

    Most people don't like them, but Hazeltine 1500s show up fairly frequently on ebay and because they aren't coveted like the ADM-3A or the VT100 they go for cheaper. Wyse terminals also show up frequently.

    The other thing that happened to serial terminals is that the "keyboard freaks" are collecting the keyboards separately from the terminals, so sometimes a seller will list the keyboard separately (ugh) hoping to cash in on that.

    Bargains can still be had on ebay if you are patient. However, I expect the situation to only continue in its current direction. Prices are likely to only increase from here as I see more and more people becoming interested in vintage computing and they all want period terminals to go with their systems.

  7. #7

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    I have a few ADM3a’s restored in good shape with new CRT’s. No door over the DIP swiches but I made some. I’ve considered adding a screen saver circuit because these terminals don’t have that feature. There’s a lot of TTL in the ADM but the service manual is good and parts aren’t unobtanium.

    When I need a terminal I generally use a VT 340 with new CRT. The keyboards can bounce or get wonky but with difficulty they can be disassembled and cleaned, which is a good opportunity to paint the shells. The CRT section is really tight inside and somewhat of a PITA to repair; the plastic is old and I broke a bezel tab and had to glue it. But it’s probably the last time I’ll be replacing the CRT. Loose keyboards are rarer for the VT 2/3/4 series than the video/terminal component.

    On that subject, make sure ALL keys are present when buying a terminal unless you are buying one for spares at a good price.

    Get the CRT’s while you can, B/W CRT’s are not terribly expensive. And as you may have guessed, I HATE screen burn.

  8. #8

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    Yeah, I don't understand the keyboard freaks at all... must be a "gamer thing".

    Although I am looking for four Hall-effect key switches for my other Silent 700 though... or a 100% working keyboard. Which also seem to be getting harder and harder to find... but I would never strip a rare working keyboard to get them.

  9. #9
    Join Date
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    Quote Originally Posted by Slob View Post
    I have a few ADM3a’s restored in good shape with new CRT’s.
    What's your source for replacement CRTs? That is good information to have.

  10. #10

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    Quote Originally Posted by legalize View Post
    From one of the photos in the auction, I infer that particular ADM-3A probably has a bad RAM chip in the screen memory and the epoxy holding the safety shield on the CRT has started to outgas, resulting in "CRT cataracts" or "CRT mold" (it's not mold).
    The VR201 suffer the same fate. Its tough to find them now without screen measles. I hot wired one off once, cleaned and reattached with clear silicone. Looked great but I would never do it again.

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