(Topic ID: 289552)

Looking for a GPE Quickscan 80 to borrow or buy

By goingincirclez

7 months ago


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  • 13 posts
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  • Latest reply 7 months ago by Cheddar
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    QS80V3A_Proto (resized).jpg

    #1 7 months ago

    I've got a project Black Hole with a dead MPU and there doesn't seem to be much in the way of "deep dive" guidance out there.

    The MPU's clock and reset sections are good, as the 6502 pulses low-then high on pin 40, and pins 39 & 37 pulse the clock. The RIOT chips pulse the same clock. But the CPU IRQ is locked high. And going from there points in many possible directions.

    I understand several years ago that Ed G-P-E made a fantastic little troubleshooting board called the "Quickscan80" to narrow these scenarios down, but these are NLA. Does anybody have one they wouldn't mind parting with? Either to sell, or even loan? I'm reasonably competent board tech as I've extensively rehabbed and rebuild numerous WMS Sys6/9/11, GTB sys3, and Bally -35 boards with success. But I'm far from an expert and this is my first System80.

    Still, I can assure due care to anyone who might consider loaning (renting) me their Quickscan80. But if purchase is my only option I'd consider that too.

    Please LMK if you can help. Thanks!

    #2 7 months ago

    Bump since I created the post at midnight, heh

    #4 7 months ago

    Thanks ForceFlow... I didn't know about that one and it looks similar.... but it isn't available anymore either.

    #5 7 months ago

    I wish I had time to finish the software....

    QS80V3A_Proto (resized).jpg
    #6 7 months ago
    Quoted from G-P-E:

    I wish I had time to finish the software....[quoted image]

    I want it. I know you are so busy Ed.

    #7 7 months ago
    Quoted from goingincirclez:

    Thanks ForceFlow... I didn't know about that one and it looks similar.... but it isn't available anymore either.

    Try PMing acebathound

    #8 7 months ago

    Way to rub it in, Ed! Was there something wrong with the old version, or are you suffering from "creeping featurism"? I guess it speaks to the quality of your product that those who got one swear by it and apparently won't part with it. But anyway, if you get to making more of these I'm sure I won't be the only one interested!

    #9 7 months ago

    I just bought one of these and it is great. There were 2 in stock when I bought about 2-3 weeks ago, but looks like they are out now. It is basically the same thing and arrived from France in about a week. Keep an eye out! I'm sure they will restock soon.

    https://www.flipprojets.fr/shop/index.php?route=product/product&product_id=67

    #10 7 months ago
    Quoted from goingincirclez:

    Way to rub it in, Ed! Was there something wrong with the old version, or are you suffering from "creeping featurism"? ...

    Gee... I *never* get accused of "feature creep" at work. Or at least not this week, yet.

    #11 7 months ago

    Using the original version of Quickscan on a system 80 board, the test unit reported a stuck high IRQ on a board I was working. However there is no other information beyond the stuck high IRQ lamp to provide additional diagnostic help. So I have some doubt that a Quickscan will help with your immediate problem of a stuck high IRQ. Once your IRQ stuck high problem is resolved the Quickscan will likely be of help.

    #12 7 months ago

    All the test fixture can do is report what it can see from the CPU side.
    Often a stuck IRQ can be caused by a bad CPU but usually identified with a bad RIOT.
    The QS80 will exercise all RAM and Registers that are writeable AND readable and will report a RIOT as good or bad depending on values returned. If the test fixture can clear the IRQ then it will set them one at a time to see if any go awry. If that works then it starts up a series of rapid IRQ tests for each IRQ.

    For those wondering about the 10M oscillator on my board -
    One 'thing' that made the QS80 difficult to design is the fact that there are quite a few Rockwell 6502 CPUs out there that do not meet the 6502 timing specifications. With the incredibly slow circuitry on the Gottlieb boards, nothing is affected by this timing issue. However, the registers on the QS80 are blindingly fast in comparison and are affected by the Rockwell timing anomaly. Not sure how the French guys get around this (or if they do) but I had to resort to retiming the CPU signals to work with fast logic.

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