Whitechapel Computer Works MG-1

tony duell ard at p850ug1.demon.co.uk
Sun Nov 30 23:53:41 CST 2014

> On 11/30/2014 12:51 AM, tony duell wrote:
> > It needs a good set of NiCd cells on the power control board to start it up.
> > If not, you have to do a 'jumpstart' involving connecting a 9V battery to a connector
> > on that board. Some owners added an external socket wired there to make it
> > easier to so this.
> I think I've seen four of the machines in total; every single one of them
> had suffered significant corrosion to the main PCB beneath because of the
> batteries.

The main problem in my experience is corrosion of the (tin plated) Molex
KK connector between the power control/battery PCB and the motherboard
This carries the system power (!) and corrosion leads to all sorts of problems
due to the fact that the 5V line is anything but.

> > There is a rare adapter which adds 3 ISA slots. 8 bit ones IIRC.
> I know the CG-200 at NMoC has such an adapter. I've actually got a photo of
> it here - it has 3x 8-bit ISA slots toward the rear of the system, as you
> say, but then there are PCB traces at the other end of the adapter board
> for three 64-pin sockets, although only one is physically fitted on NMoC's
> machine. Purpose unknown, and it'd be interesting to know if anything ever
> made use of it.

I seem to remember those connectors are essentially the 32016 bus. I've never
seen them used for anything. Maybe in a few months time when I have unpacked
all my books I can find the technical manual and see...

> That particular system has an ISA serial board and some flavour of ISA
> video board (whatever the latter is, it has 8x 41264 dual-port RAM chips,
> and there's a 20-way ribbon cable attached which runs off somewhere beneath
> the ISA adapter board). Unfortunately the machine - like the MG-1's - had
> also suffered significant corrosion.

I wonder if that's the colour video output card. Does this CG200 have the normal
MG1 motherboard in it? I seem to remember a connector on the motherboard 
that carried at least the video timing signals.


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