This weekend's haul

From: A.R. Duell <>
Date: Fri May 30 13:40:32 1997

> Does the PS/2 not have any 5.25" drive bays? Weird. :) I'm not an IBMer
> so I don't know these things, though I *think* one of the machines I used
> to do CAD work on was a PS/2 of some flavour.

No, AFAIK the PS/2 cases had (special!) 3.5" bays only.

> > The size of the drive is mainly because of the PS & case (the case is
> > *very* well RFI shielded)... the drive itself is a standard 1/2 height 360K
> > 40TKDSDD 48TPI drive, with a standard 34-pin edge connector.
> OK, that makes it useful. Would you happen to know what the pinout is of
> the 37-pin connector, so that I can try to make use of the drive without
> modification? Is it even possible to buy a matching female 37-pin
> connector?

If it's the same as the XT external floppy connector (and I think it is!),
the 34 wires of the standard floppy connector are connected to the
'bottom' (higher numbered) pins on the 37 pin D plug. Pins 1,2,20 are no
connection, pin 3 is wire 2, pin 4 is wire 4, pin 5 is wire 6, etc. Pins
21-37 are all grounded.

It's a standard DC37 connector, available from any good electronics parts
place, I think. You can get solder, PCB mount or IDC versions.


> Interesting. How are the drives interfaced to the CoCos? I've got a
> CoCo1, CoCo2, and CoCo3, but I've never found a disk drive for these
> machines.

You need a disk interface cartridge. It fits into the ROMpack slot, and
it contains a ROM containing the disk extenstions to BASIC and the disk
controller (WD1773 in later models, WD1793? in earlier ones). The disk
drive plugs into a 34 pin connector on the end of the cartridge

Late version disk interfaces (FD500 and later) work in all CoCo's. Early
interfaces need a 12V line (I forget if it's +ve or -ve) that's only
available on the CoCo1. Of course there's nothing to stop you hacking it.

> Heh. I couldn't even get mine apart, because of the two six-pointed
> screws on the bottom. The screws have a lump in the middle so I can't use
> a flat-blade screwdriver as I did when I had a similar problem opening my
> Mac 512K.

Tamperproof TORX screws. Drivers for them are available from good tool
shops in the UK - I have a reasonably complete set to deal with such

> Doug Spence

The gates in my computer are AND,OR and NOT, not Bill
Received on Fri May 30 1997 - 13:40:32 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:30:33 BST