17 Jun
2005
17 Jun
'05
4:49 a.m.
On Fri, 2005-06-17 at 00:49 +0100, Tony Duell wrote:
There certainly doesn't seem to be much sign of wear on this machine.
The plus/minus/manual carriage movement keys seem prone to jamming and I
need to figure out the source of that (possibly more foreign debris in
the mechanism somewhere)
:-)
I have no idea how it got in there; there isn't really a sufficient gap
anywhere for such a thing to fall inside. And it was *very* well buried
inside the mechanism (almost as though someone stuck it in there for
fun!)
Aha, well I can isolate and test easy enough there without any severe
dismantling of things. Can anything be done to fix the problem (short of
making new insulators)?
Yep, it's the bits outside the frames that are rather scary-looking! The
actual underside of the key bed doesn't look too bad. This machine's
fully automatic, so I suppose it's an extra stage of complexity over a
semi-automatic machine. It's got three registers, plus the multiplier
one.
Uh huh - digging around since posting that, it looks like circa 1962 is
about right.
cheers,
Jules
Question -
does anyone have service information for these machines
(yeah, right!) or useful tips on things to check over?
No psecific service information, but my first comment is that 99% of
problems with mechanical calculators are due to gummy lubricants. Worn or
broken parts are uncommon. Serondly, do not spray it with Wanton Destruction 40,
or anything else
for that matter. You will do a lot more harm than good...
I've been using sewing machine oil so far (which is the lightest stuff
I've got). I just wonder if leaving it in a (slowly circulating /
filtered?) bath of oil for a week or so would be useful for freeing
stuff up and getting all the dirt out...
So far
I've found an acorn jamming up the works (!!) and lots of dirt,
An Acorn... What, a System 1, or an Atom, or a Beeb or an Arch, or what...
(sorry, couldn't resist...) There's
some earth leakage which would be useful to track down -
possibly a break-down in cable insulation? I've not worked out what the
Most of the time, that's due to tracking across the impregnated fibre
insulators used in things like the automatic on/off swtich. Almost certainly a governor. Do not be tempted to
bypass it, many of
these machines used series wound motors which will get up to a ridiculous
speed if not controlled and do considerable damage.
Yep, I saw somewhere that 180rpm is typical for governed motor speed...
Can't say
I've ever seen such a complicated thing. Electronic circuits
don't even come close in complexity :-) I don't think I'd be up for a
I've not seen this one, but from the mechanical calculators I have been
inside, there's typically the same mechanism repeated <n> times (digit
entry, accumulator register, etc, and some control linkages, which are
typically outside the side frames. There are a lot of parts, but the
complexity is not that high. pps. Anyone
care to guess a date for this machine? I'd make a wild guess
at mid-50's but really don't know.
Sounds about right. Maybe a little later (early 1960s).