[Coco] Calling OS9/68000 gurus

Bob Devries devries.bob at gmail.com
Mon Aug 9 01:54:05 EDT 2010

I know this may be slightly off topic, but....

I need some fresh insight to repair my Secad AS-68K (OS9/68000) based on the 
ISA bus with a 68000 processor at 7 MHz.

Some time ago, it was somehow damaged. I've been working for a while to try 
to make it work again. I'm *almost* there. The Secad is set up for an EGA 
monitor, which I don't currently have, so I'm booting from a disk which has 
the TERM descriptor set to use one of the on-board serial ports which uses a 
68681 chip, and then connecting another computer to monitor the serial 

Well, the computer tries to boot. It appears to read the OS9Boot file (as 
evidenced by the approximately 6 steps of the disk head. It then beeps (it 
has an onboard audio output just for that purpose; just write to a memory 
address), and then after a short delay, goes back and re-reads the OS9Boot 
file (seeks to track 0, and steps 6 tracks again). The 6 tracks are correct; 
I know the size of the boot file, and that matches.

I'm getting no output from the serial port at all, so my guess is that 
although the boot file is being loaded, *something* is causing it not to 
start. I have read the bootfile on my MM/1 and all IDENT are  correct; all 
CRC's are correct.

Does anyone have any clues and/or suggestions for me to try?

My next direction will be to try to find a CGA graphics card, and build a 
boot for that. Sadly, I don't have drivers for a VGA card.

Regards, Bob Devries
Dalby, QLD, Australia

Besides a mathematical inclination, an exceptionally good mastery of one's 
native tongue is the most vital asset of a competent programmer.

Edsger W.Dijkstra, 18 June 1975

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