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Thread: Altair 8800 / 8800a Power Supplies

  1. #1
    Join Date
    Jun 2003
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    Northwest (UK)
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    Default Altair 8800 / 8800a Power Supplies

    Hi Folks!

    Went on the quest to pick-up some S100 boards for my IMSAI and ended up buying an Altair. As you do! The machine is currently on it's way from the US to the UK.

    Obviously the power supply is going to be 110V. I have no problem with that and already have a step down transformer. However, I'm a little worried about the 60>50hz issue. Does anybody know what transformers were used in the Altair 8800(a) machines so I can check the specs?

    Anybody running an Altair on 50hz mains?

    Cheers,
    Dave

  2. #2
    Join Date
    Dec 2011
    Location
    East Coast USA
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    The problem is you won't really know what is in the Altair till you open it up.

    The Altair had pretty crappy supplies until the later ones. Many Altair have been modified because of this, so I wouldn't count on anything till you crack it open and see.

    Cheers,
    Corey

  3. #3
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    Jun 2003
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    Default

    Hi Corey,

    Thanks for the reply. I kinda figured that might be case. I've only got the photo's to go off for now and I can't quite make out any part numbers. Power supply looks pretty standard but not sure about the capacitors. They look a bit too modern?

    http://www.ebay.co.uk/itm/322817832724

  4. #4
    Join Date
    Dec 2011
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    East Coast USA
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    Well you lucked out...

    That's not an Altair 8800A, the picture are a little weird due to the angles, but I think that's a Rev-0 Altair with an upgraded motherboard, but a really good condition early front panel. It was factory assembled which is why the serial# ends with A instead of K. Worth a lot more than you paid. You should keep an eye out for an original rev-0 motherboard/backplane and replace the one in there. Periodically you can pick them up for a few hundred dollars and in an afternoon you can put the machine back to original spec.

  5. #5
    Join Date
    Jun 2003
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    Northwest (UK)
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    Ahh, ok. I wasn't sure about it being a Rev.0 The extended motherboard threw me and I'd assumed an 8800a with the earlier silver name badge.

    Yes, it worked out to be a pretty good deal and the seller accepted a slightly lower offer too

    Will keep an eye out for an original backplane but I intend to keep it pretty much as-is. Aim is to have it hooked up to the Teletype and running BASIC from paper tape. Only change is going to be to safely pack away the three 88-4KD and stick in a more reliable static ram board.

    Cheers,
    Dave

  6. #6
    Join Date
    Dec 2011
    Location
    East Coast USA
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    Default

    Well it's not a very early one since the port holes are rounded at the edges, but it is early enough to be worth something.

  7. #7
    Join Date
    Jun 2003
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    Northwest (UK)
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    Default

    Ok, this is weird. Just thought I do a little research on early Altair systems and also tried googling the serial number of this system I've bought and I've turned up something interesting.

    Firstly, Here is the Ebay listing from which I've just bought the machine...
    http://www.ebay.co.uk/itm/322817832724

    Serial number is 221162A


    It seems like it was up for sale on Ebay back in June 2015. Spec matches the system I've just bought...
    http://www.ebay.com/itm/261896644749

    Seller is Michael Ng who produces the Newton Apple 1 reproduction boards.


    However, it was also sold on Ebay back in March 2012...
    http://www.ebay.com/itm/190651368746

    The installed cards are quite different but the rear panel is the same as it looks like a phone number is scratched into the top left corner. There is even a video linked in the Ebay auction....
    https://www.youtube.com/watch?v=_JpXcJ5bVNs

    It's Erik!

    Ok, so the machine isn't exactly original but it's certainly well travelled

    Cheers,
    Dave

  8. #8
    Join Date
    Dec 2011
    Location
    East Coast USA
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    Default

    Huh, so it started out coming from Erik. Newton had it and looks like he changed the front dress panel (I wonder now if it's a real dress panel or reproduction since it's in such good shape).

    When you get it, please take lots of high res pics so we can figure out what is going on.

  9. #9
    Join Date
    Jun 2003
    Location
    Northwest (UK)
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    Default

    Yep, will do. Probably going to be a week or two until it arrives but will post back here once it does.

    Cheers,
    Dave

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