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Recreating the Ferguson Big Board

hideehoo

Member
Joined
Aug 4, 2015
Messages
44
Location
Prior Lake, MN
As part of a recent estate sale, my son and I ended up with two Big Boards, one built, and the other almost completely bare. Stripped the bare one down, took a couple of scans on a large format flatbed and started doodling in Sprint Layout. Doesn't look to bad to replicate if anyone is interested in also rebuilding one of these on a new PCB. Couple of choices I foresee are

1. Uses 250 mil (6.35mm) spacing for all the decoupling caps. Tempted to reduce that to the more commonly available 5mm ceramic discs you find today.

2. Couple of traces are at a non 45 degree angles, so the layout will need to deviate a bit there.

3. Can't recreate the 45 degree crosshatching in Sprint for the ground planes. Should you even really be crosshatching these days?

4. The Chinese PCB fab blue soldermask I've got in the past is darker than the original Ferguson boards. Interestingly the built one that was exposed to the elements has changed color from blue to almost green.

5. Should I work things like the 4Mhz mode and other "improvements" into the design, or leave that to rework after the fact? I'm leaning towards keeping it original. The built one I have is a mess of rework wires and quite frankly I'm not sure what some of them are attempting to do.

Probably work on this over the next month or so. The built board looks really bad (stored in the corner of a garage), and I'm not sure I want to build the NOS one, so this seems like a fun way to get one of these up and running and build some new skills for replicating old PCB's.
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,225
Location
Chaffee, MO
I was always interested in the Ferguson Big Board or the Xerox 820 (820 II) back in the day. I finally caved in and bought my
Kaypro II. It has served me well over the years.

The Micro Ccornucopia Magazine (on Bitsavers as scanned PDF's) also covered the Big Boards. There software was mainly for
Kaypro's but there was also some for Big Boards (also Patches).

The only problem I see, is the lack of Floppy Drives and Floppy Media. But, you could always use the HxC or FlashFloppy that
uses the GOTEK's.

Software for the Big Boards (and the PFM Monitor) is on Bitsavers and Amaus.org

Amaus:
/S100/digital research corp/systems/ferguson big board/
/S100/digital research corp/systems/code/

/S100/xerox/systems/820/

/S100/digital research corp/systems/PFM ROM monitor
/S100/digital research corp/systems/code/


Larry
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,225
Location
Chaffee, MO
You didn't say if the Big Board included 8" or 5.25" Floppy's. If it did you need to get those backed up with
Imagedisk, Teledisk, Kryoflux, or Supercard Pro. The first two choices will require a DOS Computer.
But, you have to make sure that reading them doesn't destroy them in the process.

Larry
 

8008guy

Veteran Member
Joined
Jun 25, 2014
Messages
584
Location
Salt Lake City, Utah
If you do a run I would be interested. Back when they were originally produced I wanted one but had a young family and couldn't afford one.

Len
 

Mal

Experienced Member
Joined
Apr 3, 2008
Messages
91
@hidehoo - would you mind posting some high-resolution images of the stripped board? I am very keen to see them.
 

enrico

Experienced Member
Joined
Nov 4, 2007
Messages
119
Location
Pisa - Italy
I am very interested in having the layout as far as you have come to rebuild it.... In Italy the Ferguon Bigboard 1 was first cloned and then modified in the wiring diagram and firmware. The updates consisted of 4MHz clock, FDC 1797 and 256KB RAM. In the firmware were added in collaboration between ADE Elettronica and the Politecnico di Milano commands to manage the geometry of the disk drives. You can read the story in my web site also with English translation https://www.vintagesbc.it/vintage-computer-board/collezione/ferguson-big-board-i/ Obviously I have the firmware and the wiring diagrams of the modifications if you are interested.

Enrico - Pisa - Italy
 

gekaufman

Experienced Member
Joined
Jul 31, 2014
Messages
233
Location
New Hampshire, USA
If hideeho would be willing to loan out the bare board for a few weeks I'd be interested in having the board professionally scanned and making clones available. Likewise I have a full set of documents, firmware and a modest stock of some of the more difficult to source parts like the 1771 FDC and the 5016 baud rate generator.

I built up dozens of these boards in the early 1980's for folks and it was my first CP/M system. I still have a few here.

Many years ago I spoke with DRC by phone but they no longer had any of the original artwork for the boards.
 
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