10 Sep
2004
10 Sep
'04
6:08 p.m.
Incidentally, it always impresses me how many
clock museums
keep their exhibits running (in most cases about 70% of the clocks are
still running in my experience). And they're
not faked!
This is good, but a clock usually costs less to run than
a computer (and a lot less to run than an *old* computer).
There are also many more people willing and/or able to
sit down and understand a clock than there seem to be
who are willing/able to do the same for electronics.
This I don't understnad. Classic computers (at least not any one I've
worked on) are not that hard to understand. And if I can do it, anyone
can! Problem is that nobody seems to _want_ to understand electronics any
more (and this worries me a lot!).
My clock experience is limited to one modern mechanical
alarm clock and one electro-mechanical clock/radio/alarm
thing. Both had mechanical problems, both came apart
(given a little time and effort) and both went back
together and worked. Plus there was not much difference
between them (at least in principle, at least to the
depth that mattered in getting them functional again).
OK, let's see how you'd get on doing jobs like
Bushing a plate hole (this is suprisinging difficult the first time, the
wear on the hole is uneven in general so the centre of a worn hole is
_not_ where the centre of the bush should go).
Calulating the number of teeth on a wheel and pinion if one of the arbors
is missing.
Re-pivoting an arbor
Cutting a wheel (that's a gear for the non-horologists, I mean using a
dividing head to cut the teeth), then crossing it out (cutting the metal
out between the spokes)
Determining the correct dimensions, then making, a set of pallets.
And so on. There are simple clock repairs, there are difficult ones. Much
like computer repairs.
Computers seem to vary much more in design and have
evloved quite considerably. There is also plenty that,
potentially at least, you cannot tell just by looking.
(PALs, ASICs, custom parts, parts for which you
have no datasheet etc.).
Depends on the machine, of course. And as I've said many times, the time
to start thinking about repairs is when the machine is still operational.
That's when you pull all the PALs and ROMs and dump them (even
copy-protected PALs can be reverse-engineered, FPGAs are almost
impossible, though!). If a data sheet once existed (i.e. it's not a true
custom part) then it's likely _somebody_ still has it...
So it is certainly impressive that a clock museum
can keep many clock operational; but I doubt that
any sort of computer museum would have the resources
available to do that for old computers. It is possible
to build your own valves, but is it possible to
build a replacement valve for a specific (but now
unobtainable) valve for some old mainframe?
I couldn't do it, but I don't think it's impossible!
-tony