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Thread: PC SPRINT CARD OVER CLOCK FOR 8088 XT PC COMPUTER 5160 8 bit xt IBM 5150 5160

  1. #1

    Default PC SPRINT CARD OVER CLOCK FOR 8088 XT PC COMPUTER 5160 8 bit xt IBM 5150 5160

    There is one of these things for sale on Ebay:

    April 14th, 2012

    Item number:

    261000764118


    My question is: Does this thing actually work?

    If it does, by the looks of it, it don't look like it would be hard to reproduce, improve?

    Maybe a project for the IDE XT Guys, jusy putting that thought out there
    GEEKS WITH A GRUDGE!

  2. #2

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    Yes, it works.

    Original docs can be found here:



    I created PDFs for the artwork files, which are designed for an Epson compatible printer in graphics mode.

    Matt Carpenter did a version of this a few years ago for the PCjr. It is fairly well understood.


    Mike

  3. #3
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    FWIW,. the seller's a good guy - I've been communicating with him privately for about two weeks. We swung a good trade for an Adlib card that he had listed. He thought it was great to find someone to talk tech with, and then I told him about this place - to my knowledge he hasnt' joined yet, but he says he will... we'll see!

    Either way... he's a good guy to deal with. And I can tell you, the BIN was just as test of the waters, to see if he'd get a bite (most of his prices are that, I think - that's not to say that he doens't have a specific value in mind for them, but his BINs are what he'd like to get in a perfect world, not what he'd accept)
    ---
    Currently seeking:
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    I also collect PC and C64 Sierra On-Line software!

  4. #4

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    I was hoping that by posting that, I would dramatically move the market for the used versions. ;-0

  5. #5

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    Quote Originally Posted by mbbrutman View Post
    I was hoping that by posting that, I would dramatically move the market for the used versions. ;-0
    I think you have.
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

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    The auction may be slightly misleading, because using a 20MHz clock would give a CPU effective clock speed of 6.66MHz. The 8284 divides the clock crystal by 3. Moreover, it only works in systems with a discrete 8284.

  7. #7

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    Is one of these things worth using, any major drawbacks?
    GEEKS WITH A GRUDGE!

  8. #8
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    Quote Originally Posted by gerrydoire View Post
    Is one of these things worth using, any major drawbacks?
    That depends on how wedded you are to the original speed of your machine. The worst possibility is that you shear a pin off an 8284 or 8088/V20. However, as mbbrutman has schematics available, you could easily build one for $30 worth of parts.

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    I wanted to see how the PC SPRINT worked to see if it could be used with a 6502 cpu, when I found it years ago and only recently got a dot-matrix printer to have a go printing it, no need now, lol am I right it just overclocks the motherboard ram and cpu?

  10. #10
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    Quote Originally Posted by rorypoole View Post
    I wanted to see how the PC SPRINT worked to see if it could be used with a 6502 cpu
    It is not, unless your 6502 system uses 8284 clock generator to generate CPU clock

    Quote Originally Posted by rorypoole View Post
    am I right it just overclocks the motherboard ram and cpu?
    Yes it does overclock everything except of system timer and OSC clock (which present on ISA and used by some extension cards, e.g. CGA and Adlib).

    The board replaces 8284 clock generator with two. First one generates clocks based on 14.31818 MHz crystal (just as the standard IBM PC / XT do), this clock is used to generate PCLK (used by timer), and for normal (non-turbo) CPU clock. The second one generates clocks based on the second (22 MHz?!) crystal, which is used for turbo mode CPU clock. Remember that the CPU clock is derived by dividing the frequency by three, so the actual CPU frequency will be 4.77 MHz and 7+ MHz respectively.

    It still makes me wonder how it works with DMA... 8237 DMAC is rated for 5 MHz and overclocking it doesn't work really well. Perhaps 7 MHz is not that much of overclock.

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