Service Manual Direct 831, Direct 825 or Basic Four S/10

Armin Diehl ad at
Fri Jan 27 17:45:11 CST 2017

On 26.01.2017 21:15, Armin Diehl wrote:
> On 25.01.2017 22:01, Armin Diehl wrote:
>> finally got one of the Basic Four S10. Does someone have a service 
>> manual for these or the Direct Inc. models ? The one i got was a 
>> little bit damaged due to shipping within Europe. Found at least one 
>> transistor and one cap that broke off the video monitor board. Will 
>> try to fix that next week.
>> The Basic Four S/10 was developed and build by Direct Inc, Santa 
>> Clara, California. They sold the machine as a serial terminal 
>> (Dec/HP) as well as a terminal in combination with a CP/M 2 board.
>> Direct 825 with CP/M:
>> Direct 831 as a terminal without the second cpu/floppy controller 
>> board:
>> and the basic four s/10:
>> Btw, I'm also looking for MAI Basic Four Software for the Models 
>> 2000, 210/510/730
>> Thx
>> machine with floppy and terminal boards: 
>> ---------------------
>> Armin Diehl
>> ad at
> here the machine is shown as the first one:
> ----------------
> Grüsse
> Armin Diehl
> ad at
Made some progress. Fixed the monitor board. The base of one transistor 
and one cap were ragged by the board holding the HV transformer for the 
tube. During transport, that board broke off and flipped around in the case.

One contact problem with the power supply prevented 12V for the 
floppies. After i fixed that, the floppies wont spin. Had to lubricate 
here and there.

Created a bootdisk using Dave Dunfield's IMD, he has saved the bootdisks 
for the machine in 2005.

The machine tries to boot from that disk and it loads the software for 
the terminal board. The terminal was initialized and i got a status line 
and a cursor on the screen. After that, the floppy will run forever, no 
load of the operating system. The old CP/M disks i have here (more that 
30 years old) will not boot at all.

I tried another 720k floppy drive that is ok but that will not even spin 
up, only the select led is on while the machine tries to boot (the 
machine can boot from both drives).

Now i'm at the point were i need the service manual.

And hint ?


Armin Diehl
ad at

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