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Type: Posts; User: Dwight Elvey

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  1. An alternate way to test a capacitor is with a...

    An alternate way to test a capacitor is with a analog bridge. I have one made by GeneralRadio. It not only measure capacitor but also inductors and resistors. Having an external oscillator allows...
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    If you have a S100 extention card, you can hack a...

    If you have a S100 extention card, you can hack a memory remapper to it. It wouldn't work well in the case. If you don't mind tacking wires to your memory board, you can use Kevlar tape to isolate...
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    I don't recall where it was but it was in driving...

    I don't recall where it was but it was in driving distance from San Luis Obispo. There was a scrap yard where old IBM machines were run over by a tractor to render them as scrap material. I recall...
  4. It is likely from the frequency of the switching...

    It is likely from the frequency of the switching shifting to the audible range as the voltage drops off. It may also be caused by the switchers core going into and out of saturation as the voltage...
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    When I first started, you could see the...

    When I first started, you could see the transistors and interconnects in an optical microscope. Now you need an electron microscope.
    The fact the the chips work at all with so many parts that most...
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    Anyway, if you look at:...

    Anyway, if you look at:
    http://www.vcfed.org/forum/showthread.php?54850-Debugging-a-KIM-1-computer/page38
    and 39, you'll see the tiny boards I created to replace the 6530 of the KIM-1. Both fit...
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    I have the design. It was just that I don't have...

    I have the design. It was just that I don't have plans to make any more. It was just a one time shot to help spread the cost.
    As has been said, the 6530 had a mask ROM that was application specific....
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    Back to the original KIM-1. I would never think...

    Back to the original KIM-1. I would never think of the use of a KIM-1 for such a purpose, when there are many other methods of doing this type of project. An Arduino or similar would be fine. The...
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    Both Nvidia and AMD clearly misread the demand....

    Both Nvidia and AMD clearly misread the demand. AMD, needs to keep a tight ship. They need to order wafers far in advance and substrate silicon is tight now as well. When Intel was leading, they...
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    Ah! Mike to the rescue again. Thanks for coming...

    Ah! Mike to the rescue again. Thanks for coming in.
    Early S100 was a mess.
    Dwight
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    Hi It is a CMP M, not CPI. see may last updated...

    Hi
    It is a CMP M, not CPI. see may last updated #4 post. For the reset, you can disassemble the binary.
    All register moves are MOV. The 8080 for loading register pairs is LXI rp, ####.

    Dwight
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    I missed CPD. It is another of the memory to...

    I missed CPD. It is another of the memory to memory.loop
    loop2
    MOV A,M
    DCX HL
    XCHG
    CMP M
    JNZ Error
    DCX HL
    XCHG
    DCR C
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    Hi Hugo It looks like the binary would run on a...

    Hi Hugo
    It looks like the binary would run on a 8080. I don't think I see anything that is specific to Z80.
    Dwight

    Ops I see LDIR
    That isn't in a 8080. You'll need to code that. It reads data...
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    Current day graphic and processor have built in...

    Current day graphic and processor have built in test circuits that constantly monitor the edge of failure. They constantly readjust to keep the part at close to maximum operation. Most all of the...
  15. Electrolytics that have been sitting for a long...

    Electrolytics that have been sitting for a long time should be brought up to voltage slowly. It is because of the way they work. You power them up fast and they have to vent. Normally the seals are...
  16. It is likely one that uses DSKRDY* signal as...

    It is likely one that uses DSKRDY* signal as well.
    Dwight
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    Hi It has taken me a little while to catch up....

    Hi
    It has taken me a little while to catch up. First, you should always print a copy of the data sheet of the device you are looking at so you know what is happening. I'm going back to post 135...
  18. I've seen that before. It is the material that...

    I've seen that before. It is the material that was used that had a void. In the void it has some acid or salt. The water will defuse through the material. Since the water coming in has a lower...
  19. This sounds like a problem I've seen. Do the...

    This sounds like a problem I've seen. Do the envelopes have a white liner? If so it may be the adhesive that is suppose to hold the liner in the envelope that is failing. When it does, it leaks...
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    Ok, wind a coil. It looks like the primary and...

    Ok, wind a coil. It looks like the primary and secondary are a 1:1 and the feedback coil is 4:1, or 1/4 of the primary.
    Something like 24 turns for the primary and secondary with a 6 turn feedback....
  21. If it is turning orange and getting hot, it is...

    If it is turning orange and getting hot, it is one of two things. Either the drive device has no limiter or you have the wrong polarity for the LED. I suspect it is the wrong polarity but the fact...
  22. I always write my own assemblers. It is not that...

    I always write my own assemblers. It is not that hard. I do use Forth as one can repurpose the input parser used by the language. The assembler becomes the language. I usually write single pass...
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    Ok, don't leave us dangling, what did you do for...

    Ok, don't leave us dangling, what did you do for the coil? Your waveforms look good.

    Dwight
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    Input filter cores are a good source for such...

    Input filter cores are a good source for such toroidal cores. The wires you use can be small as the current needed for EPROM programming is generally quite small.
    Dwight
  25. The electrolytic capacitors are formed by a thin...

    The electrolytic capacitors are formed by a thin layer of aluminum oxide, formed in an electrolyte solution. When they have powered down for a long time, the oxide layer dissolves. Bringing the...
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