Spare Chips

From: A.R. Duell <>
Date: Thu May 22 19:13:14 1997

[Buying chips at hamfests....]

> I have had very good luck at the fests. Sure, some may be duds, but I
> would wager that the number is probably less than 1 in 1000 (except for

Yes, I've had good luck as well (and from a suplus place is Southampton
called 'Greenweld' who often have obscure chips at low prices). It's just
more of a risk - If I buy %random old computer for a few pounds and it
doesn't work, then I have a chance of repairing it, or at least extracting
some useful bits from it. That's not the case if I buy a dead chip.

I am quite sure that most people who sell at rallies/hamfests are honest.
Every one I've dealt with has been. It's just that the chips might have
been defective before he got them, and are being sold as untested. It's
not easy to test some devices after all...

> Actually, just about any weird old chips should be grabbed. This includes
> all of the families that are long since gone (300 series ECL, 700 series
> RTL, 800 and 900 series DTL, 4000 series _TTL_, etc.).

Agreed. I try to rescue all I can - it's amazing what does turn up. And
those are the sorts of devices I will buy at rallies - there's often no
other way to get them - and they are easy to test, and pretty difficult to
damage (e.g. by ESD). I don't tend to buy common EPROMs and micros, which
is how this thread got started.

Don't forget obscure linear devices as well. Does anyone know if the
LM379S got used in any cheap 'HiFi' amplifiers, and if so, which ones?
It's a dual 6W audio amplifier, which is used as a deflection amplifier in
the Vectrex video game, and as a servo amplifier in the Micropolis 1200
disk drives, used in PERQ2T1's and Tekky development systems (and
elsewhere). They're next to unobtainable now, so a source would be

> There is a company that still produces these chips (I forget the name),
> buying up the old masks as the original producers pull out. These new
> replacements, however, are priced for the insane and the U. S. government.

How insane? Are these price so high that I couldn't even consider buying
one, or would it be worth getting the odd device to restore a particularly
rare computer, or what?

> William Donzelli

The gates in my computer are AND,OR and NOT, not Bill
Received on Thu May 22 1997 - 19:13:14 BST

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