Date   : Mon, 13 Jul 2009 17:44:32 +0100
From   : acorn@... (Andy Ford)
Subject: Master Compact Drive Cable

Just an update to this. To cut a very long story short (pardon the pun), 
I traced this "broken directory" back to my cable. Two pins were shorted 
(one ground and I think the other was side_select, although I am not 
sure, anyway the last two wires on the cable at the (typically furthest 
away connector, and the last two pins to check) were shorted. Took a 
while to work out why but anyway all working now.

I can now read previously created ADFS disks, so all's good in that 
respect. I just need to work out the "extra" piece of wiring to get the 
led's to function (as they are not working at the moment) and I'm about 
done.

Slightly off topic but while I am here, I had a vague idea about using 
DFS on this machine too (although I do not mind really if I cannot), but 
while I had the units in bits, I popped in my spare Watford DDFS 1.54T 
that I had lying around, although attempting to access a disk just hung, 
as though the drive was not actually present. I wonder if I should get 
another Acorn 1770 DFS blown and use that (unless I have missed something)

But the drive Led's are my next main priority, then I will have a 100% 
working machine.


Andy. :)


Mike Tomlinson wrote:
> No, it'll be a pluggable resistor pack.  Of if it's soldered in, there
> will be a jumper to disable it.  I wouldn't worry about this at all.
>
> Some drives used a terminating resistance of about twice the value.
> This was sufficient to terminate the line for a single drive and two on
> the cable dropped the resistance by half, increasing the termination, to
> allow for the longer cable.
>
>