An interesting question.
If you have a module of the same age, I don't see any problem with a
My main objection, actually, is to _random_ module-swapping, as suggested
by certain HP calculator service manuals. How you can _know_ the fault
has been cured if you don't know what/where it is is beyond me.
That's what I do, but my modules are probably
smaller. One printed
circuit board holds one 3 input not-J not-K flip-flop. Another type
has four And gates.
But why not repair them? I can't believe they're that complicated to test
or debug. And I would have thought the components were a lot easier to
find than complete modules.
When I eventually run low on spare modules I will have
repair, hopefully being able to make 3 good modules out of 4 bad ones.
That is one reason why you should never throw away a defective PCB. It
might well be repairable later, or you might be able to use parts from it
to fix another board. OK, 'almost never' -- ISA cards with one ASIC and
not much else don't count :-)