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falter's latest activity

  • falter
    falter reacted to Bruce Tomlin's post in the thread Homebrew Z80 No. 3 with Like Like.
    I really was disappointed the other day to find that A8 was bad. The code is a bit less of a mess to disassemble after zeroing out those...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    Z80 A0 -> CTC Pin 18 -> SIO Pin 34 and to Both PIOs Pin 6 Z80 A1 -> CTC Pin 19 -> SIO Pin 33 and to Both PIOs Pin 5 And that's SIO Pin...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    So far for the 74LS139: Pin 9 -> Right side PIO Pin 4 Pin 10 -> Left side PIO Pin 4 Pin 11 -> SIO Pin 35 (not 33) Pin 12 -> CTC Pin 16
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    I will trace these out tonight. Thanks so much for doing this... love seeing the detective work happening! I've shown it off in a...
  • falter
    falter reacted to durgadas311's post in the thread Homebrew Z80 No. 3 with Like Like.
    Discovering more about the system, but 2-D photos aren't really working well. Need to be able to examine it in 3-D. The four loose...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    I can take more detailed pictures of the inside of the keypad box if it helps. I had originally suspected the phone cable wiring going...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    I feel pretty confident the keypad and computer go together. But I think the keypad was used before the computer came along with...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    One other question.. the EPROM this computer has, has a gold strap that runs from the EPROM window and looks like it connected to a gold...
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  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    Thanks for your thoughts! I did get some better pics of the mainboard. They are here. So my suspicion about the EPROM socket on the...
  • falter
    falter replied to the thread Homebrew Z80 No. 3.
    Man this thing is strange. So I think I was wrong about the connections between the computer and keypad. There is a power supply in...
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  • falter
    falter replied to the thread Xerox 820 boards.
    Very cool to have you here. I have both an 820 and a Big Board II. I've never gotten around to using it unfortunately. I keep hoping...
  • falter
    falter reacted to GrumpyGuy's post in the thread Xerox 820 boards with Like Like.
    I was the head technical person at DRC "back in the day" and yes the Xerox was a fully licensed design. Their idea was different...
  • falter
    Stupid question.. is there anything other than a fault in the switch that tells the floppy drive that a disk is inserted that would...
  • falter
    Thank you. I wonder why copros get so hot but not the CPU. I plugged it back in.. computer works fine..Autocad loaded up (it depends...
  • falter
    I got it! Borrowing from Adrian's Digital Basement, I took the Miniscribe and tested out the movement of the stepper motor and it was...
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