Homebuilt computer with Motorola 6809?

[TonB]

I acquired a small monitor with something below at an auction this weekend and stumped what kind of computer this is. Bought it because of the monitor on top. Expected something surveillance equipment...

It looks like a homebuilt, but has a very fine built quality, almost professional. And I don't even know which bus it uses. (Not the SS-50 or S-100)

It has a Motorola 6809 CPU and it looks like a very small altair kind system. The outer dimensions are 25 x 25 x 15 cm (about 10 x 10 x 6 Inch)
Probably from 1982 and built in The Netherlands (there is a sticker with 'SJEF' on it, a Dutch first name).
Seems a little bit late for such a built. It would be a lot more expensive than just buying a homecomputer off the shelf.
Memory about 24 KB? (3 slots with 8KB).
Only in/outputs for keyboard, video and recorder (probably).

Next I'll try to read the EPROMS.
If you can give me some hints where to look further I would be quite happy.

Whatever it will be, a fantastic find for my collection!

Some photos. Nothing cleaned yet, but almost dust free inside.


Bought it because of the monitor. (Monitor not working, yet)


Board with CPU.

Below the other boards: Video interface, IO board, ROM Board and 3 memory boards.



front view (open)


Top view

 

[jdreesen]

That videocard looks a lot like an Elekterminal.
A RS232 i/f combined with a 64x16 one-chip videochip SF.F96364
Maybe the bus is equivalent to the Elektor-bus ?

 

[TonB]

Thanks! Your reply brought me closer to a lot more information.

I think it uses the Europe Card bus (ECB: The boards measure 100 x 160 mm with DIN 41612 connectors (looks a lot like Nubus slots).

Wikipedia Europe Card Bus
The photo of the ECB computer at the wikipedia page looks almost like this model.

Meanwhile managed to back up the EPROMs: They contain some basic 'BAS8' (2x 2732), a RAM test + tape, bootrom(?) called 'MUSE' near the 6809 and a 'CHR V10 or V1.0 (21-4-83) for the video interface. (All using 2732 eproms)
Mot sure if uploading these will help, but are available.

We investigate further.

 

[Ruud]

Maybe the bus is equivalent to the Elektor-bus ?

No, I don't think so. Pin 1 of the DIN connector on the pictures of the RAM boards seems to be GROUND but pin 1 of the Elektor-bus is +5V.

 

[Dioda]

Thanks! Your reply brought me closer to a lot more information.

I think it uses the Europe Card bus (ECB: The boards measure 100 x 160 mm with DIN 41612 connectors (looks a lot like Nubus slots).

Wikipedia Europe Card Bus
The photo of the ECB computer at the wikipedia page looks almost like this model.

Meanwhile managed to back up the EPROMs: They contain some basic 'BAS8' (2x 2732), a RAM test + tape, bootrom(?) called 'MUSE' near the 6809 and a 'CHR V10 or V1.0 (21-4-83) for the video interface. (All using 2732 eproms)
Mot sure if uploading these will help, but are available.

We investigate further.

It seems it uses pin pairs 1a-c; 32a-c as ground and 2a-c; 31a-c as +5V so it can be neither ECB nor Elector bus. A similar power arrangement is used on the STE bus (IEEE-1000 bus), but it requires a quite complex interface (f.e. generating a data ack signal), and I don't think it could be achieved with such a low amount of logic on memory boards. Therefore It is some kind of custom/vendor-specific bus (also this system looks a little too professionally built for a homebuild system).

 

[MrImprovement]

There is STD Bus also, but it is a nice looking system - please keep updating us on what you find out.

 

[Pernod]

Meanwhile managed to back up the EPROMs: They contain some basic 'BAS8' (2x 2732), a RAM test + tape, bootrom(?) called 'MUSE' near the 6809 and a 'CHR V10 or V1.0 (21-4-83) for the video interface. (All using 2732 eproms)
Mot sure if uploading these will help, but are available.

Can you attach them here, may be interesting to others.

 

[TonB]

Here are the ROM dumps attached (zipped .BIN files)

Boot eprom ('MUSE' sticker on top at CPU board):
QuiteVintagecomp-MUSE-AM2732 @ DIP24.BIN

Video interface eprom (CHR V1.0 or V10 and date 21-4-'83. sticker difficult to read):
QuiteVintagecomp-CHR_V10_21_4_83(videointerface)-AM2732 @ DIP24.BIN

'RAMTEST + tape', also at CPU board:
QuiteVintagecomp-RAMTESTplusTAPE-AM2732 @ DIP24.BIN

Basic proms, 'BAS8 A0H' and 'BAS8 B0H':
QuiteVintagecomp-BAS8-A0H-AM2732 @ DIP24.BIN
QuiteVintagecomp-BAS8-B0H-AM2732 @ DIP24.BIN

Can't make much of it, except opening with an hex editor.
Not sure of the eprom at the video interface because of the little data.

 

[TonB]

It seems it uses pin pairs 1a-c; 32a-c as ground and 2a-c; 31a-c as +5V so it can be neither ECB nor Elector bus. A similar power arrangement is used on the STE bus (IEEE-1000 bus), but it requires a quite complex interface (f.e. generating a data ack signal), and I don't think it could be achieved with such a low amount of logic on memory boards. Therefore It is some kind of custom/vendor-specific bus (also this system looks a little too professionally built for a homebuild system).

I'll check the pins and power tomorrow.

 

[Pernod]

Here are the ROM dumps attached (zipped .BIN files)

Boot eprom ('MUSE' sticker on top at CPU board):
QuiteVintagecomp-MUSE-AM2732 @ DIP24.BIN

Video interface eprom (CHR V1.0 or V10 and date 21-4-'83. sticker difficult to read):
QuiteVintagecomp-CHR_V10_21_4_83(videointerface)-AM2732 @ DIP24.BIN

'RAMTEST + tape', also at CPU board:
QuiteVintagecomp-RAMTESTplusTAPE-AM2732 @ DIP24.BIN

Basic proms, 'BAS8 A0H' and 'BAS8 B0H':
QuiteVintagecomp-BAS8-A0H-AM2732 @ DIP24.BIN
QuiteVintagecomp-BAS8-B0H-AM2732 @ DIP24.BIN

Can't make much of it, except opening with an hex editor.
Not sure of the eprom at the video interface because of the little data.

Has anyone else looked at these? The MUSE ROM looks suspiciously bad, it has a reset vector of $F837 that doesn't look like valid setup code. The other ROMs look good, and have decoded the CHR ROM to reveal two character sets.

 

[Gary C]

never seen a home built computer use reference numbers on the boards

Looks custom but professionally made Eurocard system to me. Almost like an Acorn System computer but smaller.

 

[Patrick56]

Hi. I had a quick look at the Muse Rom. It looks like it is based on the Assist09 monitor from Motorola.
If you look at offset $08C9 from the beginning of the rom you'll find the ASSIST09 character string.
The beginning of the rom has what looks to be a 6809 disassembler.
I haven't looked at the other roms.
Pat

 

[Bruce Tomlin]

Has anyone else looked at these? The MUSE ROM looks suspiciously bad, it has a reset vector of $F837 that doesn't look like valid setup code.

It looks fine to me. Be sure to remember that most of the SWI instructions take an extra byte for a function code or something.

Also I think you got A0 and B0 swapped. And the "ramtest" rom seems to be position-independent code.