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Thread: Finally started

  1. #31
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    May 2018
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    Lancashire
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    Quote Originally Posted by lafos View Post
    ImageDisk has a utility to check alignment and set track 0, if you have a PC with floppy controller
    Had a look at that and it would be perfect, need to get a PC

    Another vintage machine needed

  2. #32
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    May 2018
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    Lancashire
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    Ive managed to align coarsely the first drive.

    I can format a disk in the TEAC and read and write to it in the TP drive.

    Now I have a strange issue. I want to backup the TRSDOS disk using the TEAC only then see if I can get the TP drive to boot it (as of course if I create it in the TP drive it wont be a proper test)

    So, from the book

    FORMAT :0 (Q=N)

    disk completes format. Then,

    BACKUP :0 TO :0 (which should be a mirror backup ?)

    The backup runs, but when it completes track 32, it skips to do track 36 onwards then completes the backup.

    If I try to boot from it, It wont.

    Any ideas ?

  3. #33
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    May 2018
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    Lancashire
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    Quote Originally Posted by ngtwolf View Post
    Tezza has an article on aligning the tandon drives. I did it (without a scope or an alignment disk), it's pretty easy. The easiest way i found to do it was to set it as drive 0, do the adjustment, hit reset and see if it boots a good dos disk, if not then adjust a little more and repeat. I'm not sure if it's perfect alignment doing it this way, but it worked well enough.. you can use a scope or whatever to perfect it though.

    https://classic-computers.org.nz/blo...andon-m100.htm
    Well blow me down

    After trying to align, I read the link above more carefully and followed it step by step, and guess what.

    Step 1, check the split band screw is tight, oh no its not.

    Quick tighten and its working, didnt even have to re-align as it was on the money. It looks as if this screw being loose allows a certain amount of hysteresis and when aligned at 0, wouldn't align at 20.

    Thanks wolf.

    All that remains is to re-assemble then its time to start on the MicroVAX 3300 (instead of using it as a handy table to rest my laptop on)

  4. #34
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    May 2018
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    Lancashire
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    Latest

    Disk alignment seems to be better now and have setup the FD55A in my old PC so can write disks (That was a game, PSU wonky,hdd dead and graphics card sick, but the AK74 board was good, amazing how 80's stuff works but early 2000 PC no so much). Did have problems with disks formatted in the TRS, writing ok in the PC but then not reading reliably in the TRS. Bit of work with a fridge magnet seems to have resolved it (different head size, slight alignment differences ?)

    Have been doing a little assembler, but somethings not quite right. Valid code not always assembling.

    Anyway, using copycat under a MSDOS emulator, managed to write a diagnostic disk which boots and I have a failed memory chip. Ah well. Got a batch on order (20 for 8 !) of the 128 cycle chips (I hope, MN4164P-150). Think they have just been pulled and not tested (rather than the highly suspicious China source that looks like painted and labeled chips), so i'm not expecting them all to work, but i'm hoping a few will, maybe even enough to do the 128k upgrade.

    If these chips are a bust, anyone have a reliable source ?

  5. #35
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    May 2018
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    Lancashire
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    Love how the original RAM chips have a gold label with the Tandy Corporation logo on them

    Anyone tried to remove it and stick it on a new chip

  6. #36
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    May 2018
    Location
    Lancashire
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    Bought the MN4168P-150 memory chips from here

    On ebay MN4164P-15-Page-Mode-DRAM-64KX1-150ns-NMOS-USED-2-pieces

    10.92 for 16 and all of them work.

    Have now upgraded my Model 4 to 128K and the memory diagnostic shows all four pages as healthy.

    A program I was having trouble with now works faultlessly and the drives are now fairly reliable and read/write both in the tandy and the PC.

    All done I think.

    Now to get on with the Fallout terminal emulator program.

    Does anyone have a 128K badge ?
    Last edited by Gary C; July 22nd, 2019 at 03:49 AM.

  7. #37
    Join Date
    Apr 2018
    Location
    Los Angeles, CA
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    Quote Originally Posted by Gary C View Post
    Does anyone have a 128K badge ?
    Check with Jay Newirth on here, that's where I got mine.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA

  8. #38
    Join Date
    Mar 2016
    Location
    Pikesville, Maryland
    Posts
    205

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    Quote Originally Posted by Gary C View Post
    Bought the MN4168P-150 memory chips from here

    On ebay MN4164P-15-Page-Mode-DRAM-64KX1-150ns-NMOS-USED-2-pieces

    10.92 for 16 and all of them work.

    Have now upgraded my Model 4 to 128K and the memory diagnostic shows all four pages as healthy.

    A program I was having trouble with now works faultlessly and the drives are now fairly reliable and read/write both in the tandy and the PC.

    All done I think.

    Now to get on with the Fallout terminal emulator program.

    Does anyone have a 128K badge ?
    I have them (both original and re-work)

  9. #39
    Join Date
    May 2018
    Location
    Lancashire
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    204

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    How much for original ?

    Would mean postage to the UK ?

    Thanks

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