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Thread: Superbrain vs. Model xx

  1. #1
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    Default Superbrain vs. Model xx

    Googled around for a bit but couldn't find answers. The Intertec Model xx machines (30, etc)... are these successors to the Superbrain? Are they massively different in any way?

  2. #2
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    http://www.classiccmp.org/dunfield/supbrain/index.htm indicates that the Model 30 is identical to the Superbrain II.

    Intertec also had a proposed HeadStart which was a portable 8088 and Z80 system using 3.5" disks and nothing like the Superbrain line. There were a number of other systems designed by Intertec before reinventing themselves as an IBM PC clone maker under the name Wells American. I don't have information about them.

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    Thanks! Is there anything more desirable about the original Superbrain vs. the II?

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    Original Superbrain was first so it has that. Otherwise, II is just a modest improvement on the design which started with 64k of RAM and better shielding. Either one would be fine for most purposes and a challenge to differentiate without opening the case.

    There was also the related Intertube II (same basic design with no drives as a terminal) and Amoeba (16k version with built-in cassette as word processor) which can be potential sources of spare parts. The Amoeba seems to be very scarce.

  5. #5

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    Superbrain II has lower case descenders. I think also definable character sets (don't quote me on that!)

    I actually thought the 30 was equivalent to a QD. I have a Compustar 30 boot disk and it runs on my QD spec SB I perfectly. Gives auto repeat on the keys, too.

    Why do you ask? About to acquire one?

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    Was thinking about it. Haven't been huge on CP/M machines in the past but the Superbrain is just a neat looking machine and the later models look about the same.

  7. #7

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    Well do it, then!

    They're nice machines, albeit with non standard CP/M implementation, caused by the way the hardware is set up. There is no MOVCPM.COM because it has fixed areas in upper RAM for the floppy drive buffer. It's got a sort of shared memory thing going on so that sectors read by CPU2 (which controls the floppy drives) can be passed to CPU1 (does this using bank switching). The net effect is that it is not easy to extend the BIOS when you want to add new hardware (as I do). Also of note are the undocumented routines in the BIOS. One does initialisation, the other manages disk access. Other than those, we have all the source of the various BIOSes.

    On the plus side, though:

    • They are quite pretty, especially if you get one in decent condition. Impressively huge, though!
    • The case doesn't suffer from yellowing as it is a painted surface, although the keys do.
    • Keyboard is really nice to use (especially after a good clean).
    • There is a lot of stuff out there for it, including BIOS and boot ROM disassemly and different versions of CP/M.
    • There are a large number of useful hacks (for example, to make the floppies only start up when accessed) which are easy to do.
    • The white phosphor screen is very clear and easy on the eyes.


    I think the main thing when you get one is to recap the PSU immediately. There are a lot of capacitors on that board, all of which can fail. The CPU board is sensitive to noise and electrostatic damage. If the machine hasn't been turned on for a while, check the power lines for short circuits before plugging in. There are tantalum capacitors which can fail and short circuit. They are near the RAM banks and look like diodes. Also, the boot ROM is a TMS2716, non standard thing that modern programmers can't handle. Occasionally you get corruption in the ROM which prevents boot up. If this happens, you can get an adapter board (from me) that allows you to fit a modern EEPROM to restore the boot.

    Schematics are available.

    Minimum spec to look for should be a Superbrain I QD. A II would be nice, but check the disk capacity. 340k per disk should be the minimum.
    Last edited by JonB; October 16th, 2017 at 11:30 PM.

  8. #8
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    Jon speaks the truth!
    We have suffered through Superbrain woes here but several of us are big fans.
    There is (or was? where did all the old posts go? ah- I see- in the archive) a lot of good reading on it all in
    this forum.

    JonB's post reminds me that though mine works its time to pay attention to the old caps to keep it working!
    Last edited by dmemphis; November 11th, 2017 at 05:55 PM.

  9. #9

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    Question is, did he get one?

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    I put in an offer on the Model 30 that is on ebay. I didn't like the photos.. it looked rusty.. like it has been under water. The seller insists it's just grime and took some photos with it cleaned up a bit. They autorejected my offer but suggested for a bit more I could have it. I don't know what it's worth rrally and it isn't *the* Superbrain so I'm kind of waiting them out a bit... see if they get more flexible on price. I have seen actual Superbrains go for $500-800 recently.

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