List charter mods & headcount... ;-)

From: Scott Stevens <sastevens_at_earthlink.net>
Date: Sun Jun 20 20:21:58 2004

On Wed, 16 Jun 2004 23:32:56 +0100 (BST)
ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:

> > about Windows and PCs of the 1990s. For example, see any Vesa
> > Local Bus motherboards or interface cards around anymore?
>
> There is another issue here. Many of the machines that we currently
> consider to be classices -- The 8 bit micros, PDP11s, PPD8s, HP9100s,
> etc -- are repairable. Scheamtics exist, they were built from mostly
> standard parts that are still easy to get. If I need a chip for the
> I/O interface card in my HP9830 then most likely I can still get one.
>
> This, alas, doesn't apply to commodity PCs. Custom chips abound,
> schematics don't exist (and probably wouldn't be a lot of use if the
> did). I suspect that such machines will never really be repairable.
>

This _did_ apply to a lot of commodity PC hardware up to a certain point
in time, however. I have XT and AT motherboards that only have standard
TTL and a few Intel 82xx-series chips on them. The 'chipset' machines
came during the 80286 era. I for one used to replace chips on XT
motherboards after troubleshooting signals down to IC Pins with an
oscilloscope. In fact, the early Taiwanese clone XT boards were
near-perfect copies of each other, with the exact same TTL chips placed
at the same places on the board as the IBM design. Often with the same
IC numbers on the schematic. There's only one schematic diagram needed
to troubleshoot a bunch of those boards (and I'm not talking about
boards all produced by the same cloner).
Received on Sun Jun 20 2004 - 20:21:58 BST