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Thread: Where to start?

  1. #11
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    CH,
    Do you have David Keil's Emulator, XTRS, or GP2000 Emulator installed?

    You could use those to format the Floppy's and write the Images to floppy.

    Or if you have a tweener (DOS Computer) you can use it to create the Floppy's with Imagedisk.

    There is also the GreaseWeazle that can write the Images, after you create a .SCP file of the Image.

    Larry
    Last edited by ldkraemer; January 15th, 2020 at 02:05 PM. Reason: typo

  2. #12
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    Cleveland, OH, USA
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    Quote Originally Posted by ldkraemer View Post
    CH,
    Do you have David Keil's Emulator, XTRS, or GP2000 Emulator installed?

    You could use those to format the Floppy's and write the Images to floppy.

    Or if you have a tweener (DOS Computer) you can use it to create the Floppy's with Imagedisk.

    There is also the GreaseWeazle that can write the Images, after you create a .SCP file of the Image.

    Larry
    No, I don't have any of those applications. I'll have to look them up.
    I do have machines that I could use to construct a boot disk from an IMD file but my official "tweener" met an unfortunate end last year and I have procrastinated replacing it.
    I also have the SuperCard Pro hardware that might serve to create a disk, but I have no idea where to locate an .SCP file of the OS.
    Mostly it's a limitation of unfamiliarity with the territory.

    Thanks for your suggestions.

    -CH-

  3. #13
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    Quote Originally Posted by Twospruces View Post
    What problems did you encounter?
    I bought the Model 100 first and had to replace the NiCd battery to prevent erosion of the board. At the same time I replaced some capacitors that are known to fail. After reassembly I began to notice the display was fading in and out, and could not be corrected by the contrast pot. Eventually the display went blank.

    I checked my work, looking for cold joints or bridges but didn't find any. However this time I disconnected and reconnected the keyboard and display cables and when I reassembled I found I had a display again.

    The Model 102 was sold as non-working but in fact just needed some TLC. Just like the Model 4...

    More on these topics at the Bitchin100 site.

    -CH-

  4. #14
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    Mar 2013
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    CH,
    The .SCP files are on the way to your email account. It will at least get you booting MMCPM (Montezuma
    Micro CP/M). I created the .SCP file(s) with the HxC Software's export option.

    https://hxc2001.com/download/floppy_...tor/index.html

    Scroll down until you see HxCFloppyEmulator software:

    I'm running it in Linux - Debian 64 Bit.


    Larry

  5. #15
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    Quote Originally Posted by spt87a View Post
    Could be a bad disk.

    Try holding down BREAK when powering on to get into ROM basic. Just hit enter at the CASS? and Memory? prompts. Should get a Ready prompt. This would at least confirm basic function of the motherboard.
    The disk was unformatted, and I didn't expect any boot. I just wanted to see if there would be a message.

    Eventually there was, and from the CASS? prompt, while checking the keyboard, eventually I hit the ENTER key enough to pass the CASS? and MEMORY? prompts and into ROM basic. I entered a one-liner FOR-NEXT loop and reassured myself that the machine was healthier that expected.

    Thank you for your suggestions.

    -CH-

  6. #16
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    Jun 2015
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    Sioux Falls SD
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    Look for manuals on archive.org. There's a technical reference manual for the Model 4. I never saw a service manual for the 4, but have for the 4P.

  7. #17

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    TRS-80 Model 4/4p Service manual is public domain , look at https://archive.org/details/TRS80Model4PServiceManual to get a PDF or other favorite format from the archive.org web site

    also below you will find an image of your "edge connector functions or what they are for" ;

    Last edited by Patrick Bureau; January 15th, 2020 at 07:45 PM. Reason: forgot something.
    Vintage: TRS-80 MODEL 4, 128K RAM, 360K & 720K FDD, Gotek, FreHD, GURU RS232-WIFI MODEM, DWP-510.
    Web Site: https://texastandyrestoration.com/
    Programmer Inspiron 660s, I5-3330s, 8GB Ram, 1TB HDD, BK-844USB & EP-2A-88.
    Workstation: Optiplex 7010, I5-3470s, 8GB Ram, 1TB HDD.
    Gaming: i7-8700K, 16GB, 1TB SSD, RTX 2060, Dual 27" LG IPS Monitors.

  8. #18
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    Quote Originally Posted by Patrick Bureau View Post
    TRS-80 Model 4/4p Service manual is public domain , look at https://archive.org/details/TRS80Model4PServiceManual to get a PDF or other favorite format from the archive.org web site

    also below you will find an image of your "edge connector functions or what they are for" ;

    Patrick,

    Thank you very much for this diagram. I have the cassette recorder (CR81) + cable and I have some ribbon cables with 25 DSUB termination. With those I have a way in and out of the machine while I am creating the OS disks.
    I have an MP-105 but no printer cable with an edge connector, although Larry sent me a doc describing the pinout (thanks, Larry!).
    Ah, but the Disk Expansion Jack ... That's intriguing: I know the Model II used 8-inch disk drives; can the Model 4 communicate with an 8-inch drive? If so, does it require extra hardware, such as a dedicated controller?

    Thanks again

    -CH-

  9. #19
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    Thank you to all who provided sources for documentation. I still have a lot to learn but now I have the tools to do so. I have to say I'm impressed at the breadth and quality of the docs.

    "Trash-80"? Hardly!

    -CH-

  10. #20
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    Well, we released the magic smoke this morning. I'm glad you warned me of the possibility as I was wearing clean underwear.

    Been a long time since I heard a capacitor let go. Once upon a time I was a commercial photographer and we all used "strobes",
    i.e. electronic flash, for illumination. Those had giant capacitors charged to thousands of volts. When one of those failed it was
    newsworthy.

    Haven't popped the top yet but I assume it was the filter caps. Depending on their values I may have to order from DigiKey.

    But first to see what has happened. I'll address the drive service and the clock timing issues while I'm in there.

    Thanks,

    -CH-

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