FPGA VAX update
ard at p850ug1.demon.co.uk
Sat Nov 5 19:14:22 CST 2005
> ...and DIP-based TTL (and CMOS) is more "harvestable". Before I toss out
> an old board with lots of DIPs on it, I think really hard about getting out
> the propane torch and removing the chips on it. If the chips are SMT, it
> goes into the trash without a second thought.
Why? Although the manufacturers don't recomend it, I've had no problems
removing and re-using SOICs, PLCCs, etc.
> A friend, after retirement, has made a small career of working on Ruffatti
> pipe organs. Instruments made in the 70's and 80's rely on a bunch of TTL
> and an MPU (I think it's 8086, but not sure) for the adjustable combination
> stop mechanism. The outfit that designed it for Ruffatti and did the
> programming is long gone, not having left any documentation. Fortunately,
> the logic's made of standard parts, the MPU has a well-documented
> instruction set and it's not hard to get a probe on pins to figure out
> what's going on--and one can purchase replacements. I shudder to think of
> what would have happened if these things had been FPGAs. An instrument
> like this can have a life of several hundred years and go more than 100
> years between renovation.
I am sure most of us here would much rather repair a board of TTL than
something based around essentially undocumented parts. That's one reason
I stick to classic computers, of course.
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