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Thread: Mindset repair

  1. #1
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    Default Mindset repair

    So thanks to Thomas Raguso, I finally got my hands on a Mindset keyboard yesterday (which came with another Mindset..). So I thought I'd just quickly try a power up self test. I don't have an expansion unit yet so I can't really boot anything, although the machine Thomas sent me came with a missing-label cartridge of some kind, and a 128K memory boost pack.

    Both do essentially the same thing - usually just a black screen with no signs of life ( ). Occasionally I get a solid color screen, blue or magenta. I grabbed the Mindset service manual from bitsavers and it says if there is no video at all to change U42 and U43, which are, I believe, the custom graphics chips the Mindset uses. I tried swapping them between the two machines but got no change.

    So I checked the PSU next. The manual lays out the following:

    psuvoltages.jpg

    It says further:

    4) Plug in the System Unit power cord.
    S) The voltages should appear at this time without
    turning on the power switch at the keyboard.
    6) Record the voltages. The Trkl Chg voltage should be a little high, about 5.2 volts.
    7) Turn on the power switch at the keyboard. The voltages should remain the same as in step 5~
    except the Trkl Chg will be normal.

    I take that to mean that voltages, save for the trickle charge (not sure what that one does) should be same with power on or off. But on both Mindsets, the +12V is +10V with power off, rising to +11.5V with power on. Does that seem reasonable?

    I'm also curious what the trickle charge would be charging exactly... a battery? I don't see one anywhere. That could prevent the thing from booting..

    EDIT: Looks like they had some NVRAM carts that had a battery. I bet that's what the trickle charge is for.
    Last edited by falter; November 9th, 2019 at 11:52 AM.

  2. #2
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    Default

    I dumped the ROMs on the 'mystery cart'. I don't see a lot I recognize but on the fourth ROM I see stuff that looks somewhat English. Maybe the GWBASIC cart?

    Anyway here they are -- too large to post:

    https://drive.google.com/drive/folde...I7?usp=sharing

  3. #3
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    Default

    it is a video titler cartridge

    B:TEXTFILE.TXT
    SORRY..I CANNOT DO THAT...
    I CANNOT OPEN THE FILE
    I CANNOT READ THE FILE
    ENTER THE SEQUENCE NAME TO SAVE
    THE DISK IS FULL, TRY ANOTHER
    DO YOU REALLY WANT TO LOAD A SEQUENCE?
    ENTER THE NAME OF THE SEQUENCE TO LOAD
    DO YOU REALLY WANT TO LOAD A FONT?
    ENTER THE NAME OF THE FONT TO LOAD
    DO YOU REALLY WANT TO SAVE A SEQUENCE?
    ENABLE GENLOCKING?
    MINDSET VIDEO TITLER
    Version 1.06
    (c) Copyright 1985, Mindset Corp.
    ARE YOU USING A PREVIEW MONITOR?
    ccc111
    MINDSET
    *** NEW FILE ***
    USE CURSOR KEYS TO SET
    LEFT MARGIN AND BASELINE
    PRESS RETURN WHEN FINISHED
    ENTER TEXT:
    PGUP/PGDN=SELECT PAGE
    =SELECT LINE
    TYPE NAME OF FILE:

    >

    DO YOU REALLY WANT TO QUIT?
    DO YOU REALLY WANT TO RESTART?
    HELP ME...
    (C) COPYRIGHT 1985, STEVEN BRESS
    (P) PERFORMANCE 1985, STEVEN BRESS


    ROLL
    OFF
    CRAWL
    FADE
    CUT
    TYPE
    NEW VALUE =
    TESTING
    SAVPAG=
    SAVLIN=
    RSTPAG=
    RSTLIN=
    SREGEN=
    0123456789ABCDEF
    2DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD

    COLOR2
    COLOR3
    COLOR4
    R/G/B = LF/RT ARROWS
    LEVEL = UP/DN ARROWS
    "RETURN" TO EXIT
    F1: LOAD SEQUENCE
    F2: SAVE SEQUENCE
    F3: RUN SEQUENCE
    F5: PAGE PREVIEW
    F6: MANUAL MODE
    F10: RESTART
    ESC TO EXIT
    F1: COLOR 1 =
    F2: COLOR 2 =
    F3: COLOR 3 =
    F4: COLOR 4 =
    ESC TO EXIT
    F1: CLR SCRN =
    F2: KEY =
    F3: BASELINE =
    F4: LF MARG =
    F5: RT MARG =
    F10: PAGE MARK
    ESC TO EXIT
    F1: CHAR COL =
    F2: FONT =
    SIZE
    F6: POSITION =
    F7: P-OFFSET =
    F8: LINE SPC =
    F9: CHAR SPC =
    ESC TO EXIT
    F1: EDGE COL =
    F2: CHAR 3D =
    F3: DROP SHA =
    F4: BORDER =
    F6: H-OFFSET =
    F7: V-OFFSET =
    ESC TO EXIT
    F1: MODE =
    F2: SPEED =
    F3: BEGIN =
    F4: END =
    F5: TIMER =
    F6: LINK =
    ESC TO EXIT
    SYSTEM
    PAGE
    COLOR
    MOTION
    LINE
    EDGES
    PAGE
    LINE
    TEXTFILEASC

  4. #4
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    How did you do that? Thanks Al!

    Is this already captured somewhere? Hopefully if not I've added to the base of software.

  5. #5
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    You know, come to think of it.. I wonder if maybe the whole video production thing is part of my problem. Both of these machines were specifically modified for video production - they have little daughterboards that connect to that EXT SYNC port. I wonder if they are changed to require specific hardware or adapters to get video onscreen.

  6. #6
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    Beingthe M* gets turned on by the k/b, and not a switchon the p/s, once you plug it in a voltage is required for the chip/s that monitor the keyboard for a power on event. I assume that's what tbe trickle charge is for. The supervising chip inside the M*, I want to say it's an 8052 or something ... is thee such a thing? Anyway I've been told the power supplies are crap, it certainly has been my experience. So you may want to look into testing your units with something more reliable. I have 2 M*s also, need to get busy with all that soon.

  7. #7
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    Quote Originally Posted by falter View Post
    How did you do that? Thanks Al!

    Is this already captured somewhere? Hopefully if not I've added to the base of software.
    I'm going to throw it on bitsavers today. I've got a few tools for merging roms. 1,3 and 2,4 are 16-bit pairs

    Power is always supplied to the keyboard, that is why they warn you in the manual to not plug in the keyboard if
    the unit is plugged in.

  8. #8
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    Oops. I may or may not have plugged in the keyboard while the unit was plugged in. I can't remember.

    It's odd that both machines suffer the exact same issue.. so that's got me wondering if it is something common to both.. like the keyboard.

  9. #9
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    Hmm... so I'm reading the service manual for the Mindset, and it's saying that on power up, the screen goes blank, and it does a series of tests, *before* going to the init screen. So I'm wondering if I'm not waiting long enough. I remember this tripping me up on my 5150.. I forgot that there was no post screen, but it did have a blinking cursor.

    I wish I could find a video of the Mindset powering up from scratch. 8bitguy's video makes it appear like it goes straight to the Mindset logo on power up, but I think he edited that.

  10. #10
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    As I recall it doesn't take long for the (MINDSET) logo to start twirling around the screen. I sold my only working unit to some crazy Frenchman about 7 years ago. In fact it had stopped working mysteriously. Common to computers sitting in storage.

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