On Thu, Oct 1, 2009 at 4:59 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am also getting somewhat fed up with this idea that
classic computers
are difficult to repair (or worse 'can't be repaired'). In general it is
easier to find parts for older machines that new ones. Most of the bits
(at least those that are likely to fail) for 1960's and 1970's machines
are not hard to find. But just try finding components for 1990's
machines.
Agreed for many parts of 1990s machines, but as for 1960s and 1970s
DEC machines in particular (the subject I know more about than
others), there are a few parts here and there that are getting
difficult to find without robbing them from other machines - Omnibus
buffers come to mind first, and certain parts from the -8/i and -8/L
era, like the 74H40 or the 7482. They aren't complete unobtanium yet,
but they are nowhere near as easy to find as they were 10 years ago.
Mostly, though, for that era, I find that 7474s, 7400s, and one or two
other TTL parts are the most likely to turn up with one or more bad
gates when I start debugging things made from M-series modules. Those
are not hard to find, and not difficult at all to replace.
-ethan