Date   : Thu, 08 Nov 2007 20:14:26 +0000
From   : zeem.uk@... (Alex Taylor)
Subject: Disc interface problem [was Manufacturing fault]

I bridged the bent pin to the copper track with a blob of solder, and
the machine boots up fine now...

Except that disc access causes the machine to hang. The disc drive
motor doesn't spin, and I have one drive that the light comes on and
another that doesn't. I've swapped out all the socketed disc chips
with known-good ones and it still won't work. I have also discovered
that the 'dead' 8271 isn't actually dead at all.

I've got the service manual and circuit diagram, I've been poking
round the board with a very old 'scope (it's got valves in it).
However I'm not entirely certain what I should be looking for - does
anyone have any ideas? There are some extremely knowledgeable people
on here and I'd like to pick their brains for ideas!

-- 
Alex Taylor