Nascom 2 floppy drive usefulness...
julesrichardsonuk at yahoo.co.uk
Tue Jun 7 06:42:36 CDT 2005
On Mon, 2005-06-06 at 23:55 +0100, Tony Duell wrote:
> > Urgh. I can't decide whether to add a connector for a floppy disk to the
> > connector panel on this Nascom 2 case that I'm building. I don't *have*
> I wouldn't bother. My Nascom doesn't have an FDC either.
Yes, I think I'm leaning toward that point of view too.
> > a FDC board for it anyway, plus I only have a 2-slot backplane (at the
> > moment; there's room in the box for 7 or 8 boards probably).
> Let me guess, you've got a DRAM card in the other slot.
How did you know? Yep, that's the setup. :)
> At one point, 4118 SRAM chips, used on the main Nascom board, were very
> hard to get. The machine was supplied with none of said chip (or maybe
> one, used in the video circuit, I forget), but with a 16K DRAM board and
> a 2 slot backplane.
Yeppers. There's one 4118 on this one for video, but also a 4118 in one
of the memory sockets on the CPU board. Six ROM chips on the CPU board
too, plus another one on the memory board (although I notice the memory
board one has a bent pin that isn't actually making contact with the
socket, so I doubt that one ever did anything!)
> It is possible to do a cut-n-jumper mod to put 6116s in the Nascom board,
> I believe.
More than likely. Or make up a carrier board that just plugs into the
normal sockets. On the jumper front, it's interesting they went for a
wider pin pitch than is normal - on this board the constructor has bent
pins over and soldered them together which seems a bit bodgy, but I
don't have any jumpers that will fit that pin pitch. I'll have to see
what was done on the ones we have at Bletchley.
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