Collection policy was Re: No space for vinatge computers in

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sun May 25 16:10:51 2003

> > Can somebody please explain to me why it is so difficult to _learn_ these
> > skills? I will admit I've enver worked on a 1950's computer (the oldest
> > machine I've worked on dates from 1969 [1]), but I don't see why I'd find
> > it impossible given a little bit of time to learn the tricks that were
> > used then.
> I can't see why either - if they used valves (vacuum tubes), the tubes
> should still be available NOS or used, same for the valve bases. If the
> bases had been smashed, a schematic would be damn useful.

Even then you'd not be totally lost without a schematic if you knew the
type of valve that was supposed to go there (quite likely to be a double
triode, actually). The heater connections should be darn obvious, and you
can easily distinguish grid from anode from cathode with a little
practice. The only problem would be keeping the right anode/grid/cathode
together.

I suspect if the holder was broken into a fairly small number of pieces
you could fit them back together well enough to work out which pin was which.

Anway, can somebody please tell me how running a machine (as opposed to
having it on statick display) is going to cause valve holders to break in
half?

> If it's transistor based, I'd just trace the circuit...
>
> > [1] An HP9100B. I had to start out by writing the repair manual...
> The oldest machine I've worked on... Hmm... That's a tough one... I guess
> that would be the Jupiter Cantab "Ace" computer I'm restoring^W rebuiling.

Oh, a relatively new machine (must be, it's got one of those new-fangled
microprocessors [1] in it) :-)

[1] As opposed to an old-fashioned microprocessor, meaning a sequencer
running microcode. Both DEC and HP used the word in this sense in the 1970s.

-tony
Received on Sun May 25 2003 - 16:10:51 BST