Jerry NY2KW Jerry O. Stern wrote:
I believe the greatest issue with maintaining the 87A further down the road
are the hard programmed PALs (16 and 20) that as I understand cannot be read
or cloned. Anyone have any success?
Everything and anything can be done using RTL logic, although a bit
slow it can simultaneously monitor hundreds of inputs simultaneously
without poling, and are made of only resistors transistors and possibly
diodes, they can include LEDs showing control ladder progress.
Such logic can be spread out on one single layer board easily observed.
PALs (and GALs) are the same basic logic on one silicon die and not a
ROM.
Just because you can do something is not a reason to do it.
RTL logic boards should be infinitely maintainable, (if documented)
custom made integrated circuit components insure that will not be
possible. Few companies last 40 or 50 years and few companies can
maintain anything that they made 20 years ago.
Off of the shelf parts construction increases equipment's eventual
value. The failure of unobtainable parts can only render the equipment
ready to be redesigned with RTL logic or some such.
RTL = Resistor Transistor Logic
--
Ron KA4INM - Youvan's corollary:
Every action results in unwanted side effects.
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