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Digital Group Video Card Availability?

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
Couple of questions related to this video card that was initially designed for the Mark-8, but also used with other systems, such as the SCELBI. I'm interested in having one to go with my growing array of SCELBI peripheral devices.

1) Does anyone have or know of one that may be for sale?

2) I'm pretty much assuming that the answer to 1 will be no, so am considering building a reproduction. The information needed is already available, so that isn't an issue. Is anyone else on this list interested in building a reproduction? If I can't find an original, once I get the CAD work done, I'd be building a small batch, but the size of the batch partly depends upon interest in the hobby community. More people interested equals lower per unit cost.

regards,
Mike Willegal
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
that is a later system, which I understand, has an evolved version of the video card in it

-Mike
 

falter

Veteran Member
Joined
Jan 22, 2011
Messages
5,623
Location
Vancouver, BC
Pretty much the only person I know of that has one is Bryan (Byte Collector). I'm a big dg fan and I've never seen one in the wild. I expect I won't.. they look too much like random circuit board junk to be something people will save.

I'm actually working on a replica myself for my Mark-8 project... basically borrowing from scans and such from Bryan's site. I want mine on vintage PCB stock so it looks correct, but I'd probably be interested in a 'produced' version too.
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
A short update on my Digital Group video card project.

I have acquired all the really hard to source parts, which wasn't too difficult or costly. I have also started on the PCB layout. Seems like no real blockers in sight. It will be interesting to see if there is much difference between the schematics and the board pictured at: https://bytecollector.com/m8_docs.htm

The PCB layout might take a while, as I have a lot of different projects competing for my limited free time.

regards,
Mike Willegal
 

8008guy

Veteran Member
Joined
Jun 25, 2014
Messages
584
Location
Salt Lake City, Utah
Hi Mike, a few years back I designed a video card that is compatable with my Mark 8. It is all mostly ttl. I use one of the ic sync generators available at the time. The only "cheat" was a modern negitive voltage generator for the -12 sync generator. I designed and built a pcb for mine. If you are interested I can send you the info.
 

8008guy

Veteran Member
Joined
Jun 25, 2014
Messages
584
Location
Salt Lake City, Utah
Oh, and BTW if you design a video card for the Scelbi I am interested in a board.

Are you going to do a run of any more keyboards?

Len
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
The retro keyboard idea is something I've started and stopped about 3 or 4 times over the last decade. I think I keep stopping mostly because of the cost of quality keycaps and keyswitches.

I could share the CAD file/Gerber files of the Datanetics Rev B, if anyone is interested in making a batch. I'm not likely to do it because you basically have to part out 2 Apple II plus keyboards, just to find enough key switches to build one.

regards,
Mike Willegal


Oh, and BTW if you design a video card for the Scelbi I am interested in a board.

Are you going to do a run of any more keyboards?

Len
 

glitch

Veteran Member
Joined
Feb 1, 2010
Messages
4,964
Location
Central VA
Dave Fenyes over at osiweb.org has done a run of keycaps for a new OSI keyboard. The OSI uses just a key matrix, we'd been thinking it might be neat to have a microprocessor controller that turns the OSI key matrix into a parallel ASCII keyboard, since those are getting expensive and hard to find. Perhaps there's enough interest between all the different groups that might want vintage-style keyboards to do a larger run and get the price down?
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
Reproduction Digital Group Video Cards on order

Reproduction Digital Group Video Cards on order

I finished the reproduction Digital Group Video Card PCB layout a few months ago. This summer, I've been busy with other projects, but I've finally ordered a batch of PCBs. I should have them in hand in another week or so. I have all components in hand or on order. I've found the 5 MhZ crystal is not exactly common. I currently have a few on backorder at Mouser. Expected ship date is early December, so I may not be able to fully check out this card for a while.

I don't expect the software to be very difficult, as the hardware interface is very basic. It looks you need to write out the whole page of display data, if you want to change any characters or do anything like scrolling. The easiest thing might be to keep a mirror of video memory in main memory and write out the whole thing anytime that there is a change.

Stay tuned, keep an eye on my blog for updates: www.willegal.net/blog

regards,
Mike Willegal
 

8008guy

Veteran Member
Joined
Jun 25, 2014
Messages
584
Location
Salt Lake City, Utah
Mike,

I'd be interesred in a pcb.

Len

I finished the reproduction Digital Group Video Card PCB layout a few months ago. This summer, I've been busy with other projects, but I've finally ordered a batch of PCBs. I should have them in hand in another week or so. I have all components in hand or on order. I've found the 5 MhZ crystal is not exactly common. I currently have a few on backorder at Mouser. Expected ship date is early December, so I may not be able to fully check out this card for a while.

I don't expect the software to be very difficult, as the hardware interface is very basic. It looks you need to write out the whole page of display data, if you want to change any characters or do anything like scrolling. The easiest thing might be to keep a mirror of video memory in main memory and write out the whole thing anytime that there is a change.

Stay tuned, keep an eye on my blog for updates: www.willegal.net/blog

regards,
Mike Willegal
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
I have one of my reproduction Digital Group Video cards working and am making the rest of the batch available for $50 each (domestic USA only, international shipping rates have gone out of sight and it always was a pain to deal with customs). See my blog for the latest information on this board.

Note that I don't expect I'll be making any more runs of these cards after this batch of 20.

www.willegal.net/blog

regards,
Mike Willegal
 

mwillegal

Experienced Member
Joined
May 27, 2008
Messages
233
documentation is available, though currently not in one place. Once I finish my enclosure, I'm going to put together everything I have into one doc.

the bom and layout from my blog is accurate.
schematics can be found online: https://bytecollector.com/archive/mark_8/My_Mark-8_Info/DigitalGroupPacket/dg_packet.pdf

For now, I highly recommend reviewing my blog posts on the topic, though the board works as designed, building, powering and interfacing it required a bit of creativity.

regards,
Mike Willegal

Is there a final schematic, bom, and layout available?

Len
 
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