12 Jun
2001
12 Jun
'01
3:37 p.m.
I recently was given a Western Digital Hard Disk 20AP, obviously intended for
use with an Apple computer of some sort. It identifies itself as a Western
Digital WD1006-something-or-other but doesn't spin up, and that suggests to me
that there might be an interesting bridge controller in this box.
Unfortunately, I don't know how to open the box. Does anybody know how that
might be done? Does anybody know how to operate this device (low-level details,
not Apple-user instructions)?
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, June 12, 2001 4:33 PM
Subject: Re: Ebay horror ...
may
>
> I won't say you're alone there, but I've more often than not seen
people,
> particularly people paid to do this sort of thing, isolate faults to the
board
> level by swapping boards, then sending the board
off for depot repair. I
guess
if you
don't mind that the machine is down until the board is fixed then it
doesn't matter, but if that's the case, the machine isn't that important.
Mnay people have tried to convince me that board-swapping is worthwhile,
none have ever succeeded. I've tried it twice, and on both occasions it
was a total waste of time. It didn't cure the fault, it didn't tell me
where the fault was (in fact in one case it made me even more confused).
I had to spend the time to find the real fault anyway. And if I'd started
doing that rather than swapping boards I'd have had the system running
much sooned.
And on serveral occasions I've managed to _repair_ the old board using
components sitting around on my workbench or in the junk box before the
field servoid has managed to order the right replacement board, let alone
actually have it in his hand.
However, you are also missing a _very_ large point here. Whether or not
component level diagnosis/repair is faster or slower is _irrelevent_ to
me. I enjoy component level repair. I enjoy tracing faults. I enjoy
repairing things that have been claimed to be unrepairable.
It's a hobby. In general, it doesn't matter if one of my classics has
some downtime. I'm not running them all 24/7 anyway. Nobody else is
depending on my machines. So if I have a fault and it takes me a couple
of weeks to repair it (remember I can't spend all my time repairing
computers :-)), so what?
>
> Having spares of everything is a strategy for keeping a system running. It
A complete second system which you can use for backup is one thing. A
collection of parts that you randomly swap into a faulty system is
something else. The former is useful, the latter is IMHO not a way to
maintain a reliable machine. Certainly if I was depending on the results
from a system, I would not depend on a system which only seemed to be
working. And in general board swapping is done by replacing modules until
the fault _seems_ to have gone away -- the machine boots and passes
diagnostics. The real fault is not found, it is not known that it has
been put right. No thanks!
I've posted my horror stories often enough -- find them in the archives
if you want them. Suffice it to say I've had too many problems caused
directly or indirectly by board-swapping to ever want to do it again.
-tony