Date   : Thu, 08 Nov 2007 07:47:58 +0000 (GMT)
From   : info@... (Sprow)
Subject: Manufacturing fault

In article <d8834d20711071530i7a2c0372q664fbc7e239bd968@...>,
   Alex Taylor <zeem.uk@...> wrote:
> I stayed late at work today [...] when I suddenly
> spotted ... one of the pins for the 8271's socket doesn't go into the
> hole in the PCB. It's bent out at a right angle underneath the socket.
>
> I thought that it was funny that it's taken until 2007 - 24 years -
> for a machine made in 1983 to have such a glaring production error
> found.

That doesn't surprise me at all. If as you say the machine started life as
an Econet only machine then it's unlikely that the disc interface got much
test coverage at all.

I suspect the bare PCB was tested for shorts & opens, probably passed fine,
but to test empty sockets automatically would require a bed of nails
descending from the top into the 40 empty holes.

There's also the problem that the pressure of the bed of nails (if used at
all) may well press down the socket far enough to make contact, passing the
test anyway!

It's not clear where the bent leg came from, whether it was damaged stock
inserted by hand or whether it just missed the hole but was crushed out of
shape by the automatic insertion machine.

The fault finding section in the service guide even refers to it (checking
for pins bent under) so it was clearly a known problem back then.

Had they used decent turned pin sockets it would all be fine,
Sprow.