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Type: Posts; User: Dwight Elvey

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  1. Replies
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    These older development systems are rare and...

    These older development systems are rare and special. Don't necessarily think of that as meaning valuable. I always think of them as being worth saving. They were not just some machine turned out by...
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    The reference to Santa was more of a joke. I only...

    The reference to Santa was more of a joke. I only meant that a *.TXT file would be considered a generic text file that was like ASCII. Being generic, it could be used for anything, even a message to...
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    There is no standard. Does the machine have a...

    There is no standard. Does the machine have a monitor. Maybe you could look at the raw data of the file to see if there was anything different than ASCII. The name .BAS could only be a way to...
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    I wonder if the source BASIC files are usually a...

    I wonder if the source BASIC files are usually a *.TXT file, while the compiled BASIC files have *.BAS. Many of the older BASICs would create a tokenized form of the BASIC program for faster...
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    DRAM was cheaper but still had a high rate of...

    DRAM was cheaper but still had a high rate of failure, as did early static.
    Socketing DRAM made sense. I suspect the other reason made sense for other parts, like the TTL.
    Dwight
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    It is using MC3486/87 chips. These would be used...

    It is using MC3486/87 chips. These would be used for differential RS485 or RS422, not RS432 signals.
    It is not your ordinary serial card, regardless of what the connector looks like.
    Dwight
  7. My first computer was a Poly88. It only had two...

    My first computer was a Poly88. It only had two lights and 2 switches. One was power and a light. The other was a reset button. It also had a light but I don't think I ever thought about what it was...
  8. Well, now we know what the two different power...

    Well, now we know what the two different power supplies look like. We should be able to tell you if it was wired correctly.
    Dwight
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    The CRTC running indicates that the CPU got far...

    The CRTC running indicates that the CPU got far enough to initialize the CRTC. It may or may not be working after that. The processor is likely good but you may still have a problem with RAM or ROM....
  10. I'm thinking of the later Micral computers, not...

    I'm thinking of the later Micral computers, not the first ones.
    Dwight
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    See:...

    See: http://www.retrotechnology.com/dri/torode_designs.html
    on Herb's site.
    Dwight
  12. The KIM-1 was just reformatted LED lights. The...

    The KIM-1 was just reformatted LED lights.
    The French machine and the Sphere-1 were clearly a complete change.
    Dwight
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    I mentioned several possible setups. Which one?...

    I mentioned several possible setups. Which one?
    Dwight
  14. The Poly 88 was claimed to be one of the first...

    The Poly 88 was claimed to be one of the first S-100 computers with only two switches, a power and reset, on the case. It had a boot ROM that included a monitor to load programs and debug.
    Dwight
  15. Although, UV bleaches the surface, I understand...

    Although, UV bleaches the surface, I understand that it also exposes the surface to greater oxidation, later. I think we also need to look at how fast the plastic ages to yellow again.
    Also, does it...
  16. Interrupts off and not depending on a stack?...

    Interrupts off and not depending on a stack?
    Dwight
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    The port 0FFH is usually the lights on the front...

    The port 0FFH is usually the lights on the front panel ( upper left ). It seems that the lights are inverted ( BrainFade ). Light is 0 and not is 1 ??
    Easy enough to test. Out a 55 in A and write it...
  18. If there is an issue with the refresh, it is good...

    If there is an issue with the refresh, it is good to wait. It is a typical test of DRAM. It is even a typical test for static RAM( but for a different problem ).
    Dwight
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    It would most likely make a better flywheel than...

    It would most likely make a better flywheel than the original. One might have oxidation issues over time with the rubber of the belt but the added mass should be welcome for the flywheel purpose....
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    As for the horizontal problem, it is again...

    As for the horizontal problem, it is again something for you to look at with your scope.
    Dwight
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    I suspect the keyboard make ASCII parallel. I...

    I suspect the keyboard make ASCII parallel. I recall from before that when you hit a key, you said that it held the value. You should be able to probe the address in and the data out of the keyboard...
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    Most all micro-prototyping boards that use...

    Most all micro-prototyping boards that use cassette use Kansas City format or Byte format or modification of it.
    Again, yet another reason to lock your logic probe in the desk and start looking at...
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    I still would like to understand what the EPROMs...

    I still would like to understand what the EPROMs are for. Once you have things stable, I think we can do some scope work and resolve what their purpose was. It is still funny that they are there....
  24. I guess the thing is to not make something that...

    I guess the thing is to not make something that everyone wants, at least if you want to make a living. I'd hate to be in the position of making something that someone in China found lucrative. I'm...
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    Wow, I saw S records. The worst is, it may be...

    Wow, I saw S records.
    The worst is, it may be something close to the socket. Hopefully it is the socket.
    Dwight
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