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Really odd vintage video chip... TRANSCIENCE 2818C IC-0012 8209 — Parallax Forums

Really odd vintage video chip... TRANSCIENCE 2818C IC-0012 8209

RobotWorkshopRobotWorkshop Posts: 2,307
edited 2012-08-07 08:23 in General Discussion
I just acquired an old Rockwell R6500 AIM-65 system. Overall it is in good original condition and I have the system working. Along with it there were two hand wired expansion boards. One is a clock/calendar and the other looks like a video board. I've seen quite a few odd video chips used in old systems but this board has one that I've never heard of. It is a 28-pin DIP with the following writing on the top:


TRANSCIENCE

2818C IC-0012

8209


Anyone have any idea what this or know if a datasheet is available? If I can find out enough details I thought it would be fun to try and get this working too.

Robert

Comments

  • NWCCTVNWCCTV Posts: 3,629
    edited 2012-08-01 22:51
    Try this site. I have used several times. http://173.236.255.77/search.php?part=-2818-2&stype=part&page=2

    Try the part number only without the Transcience. Leave out the 8209 first. If it finds it then you can look for the 8209.
  • whickerwhicker Posts: 749
    edited 2012-08-01 23:37
    are you sure that 8209 doesn't mean manufactured on the 9th week of 1982? does this seem logical?
  • NWCCTVNWCCTV Posts: 3,629
    edited 2012-08-02 00:14
    Yes, That does. Did you find the IC there?
  • potatoheadpotatohead Posts: 10,261
    edited 2012-08-02 00:45
    Can you get a photo of this board? I did some reading up on expansions typical for the time. Seems to me this chip may well just be an addressable character generator. A big clue would be the video output circuit being traced back to it, as opposed to some discrete logic, xtal, etc...

    Well, maybe. That's too many pins. The ones I did see were fewer pins... confusing. And a difficult part. Could find no trace, though I did eventually find out there were several video add-ons made. None of them seemed to incorporate a chip like that.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-08-02 08:41
    My guess is that it's a custom ROM or custom-programmed OTP EPROM. Having a pinout would support (or quickly disprove) that conjecture.

    -Phil
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2012-08-02 10:36
    I'll see if I can get a picture of the board over the weekend. The small video board with this chip is mounted to a protoboard with a few TTL glue chips to interface it with the AIM-65 expansion port. I noticed two wires that were broken off but I can see where they go and can fix it. However with no docs on the main chip it will be hard to do anything with it. This is really a bizarre chip and I'm really curious what it is and what it can do. At first glance I thought it may have used an old 1861 Pixie chip for the video but as I recall those are only 24 pin chips and this one has 28.
  • potatoheadpotatohead Posts: 10,261
    edited 2012-08-02 10:52
    I'm curious too. Looking forward to the pics.
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2012-08-07 04:44
    Ok, here are some pictures of the board. Anyone know what that large 28-pin chip is? I think it is is some video chip but I still can't find any data on it.

    vid1.jpg


    vid2.jpg


    vid3.jpg
    vid3.jpg
    1024 x 705 - 161K
    vid1.jpg
    1024 x 768 - 127K
    vid2.jpg
    1024 x 672 - 134K
  • potatoheadpotatohead Posts: 10,261
    edited 2012-08-07 08:14
    http://www.google.com/patents/US4143324 The Transcience guys were into all sorts of RF type things. Found a patent reference thinking maybe that's another avenue for clues. There are probably more, but I didn't have time to look.

    I had trouble reading the other chips nearby. Looks like a PLL frequency synth and dual op-amp of some kind... It's weird, because it all looks a lot like an RF circuit to me so far.

    Good luck! Sure was fun peering at it. :)
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2012-08-07 08:23
    Thanks for the update. I suppose it could be something RF related if the original owner was a HAM radio operator. When I first looked at it I was thinking a video board with an RF modulator built in. Unless I can find some data on the chip it may still be a mystery. I'll keep looking.

    Robert
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