5 Sep
2011
5 Sep
'11
2:03 p.m.
I have a pair of Olivetti Underwood 288s (10-key 7
digit input, 8 digit
output adding machines), one of which I got from list member Patrick
Finnegan a couple of years ago, and one which I found in a local thrift
store this summer. Finding the second one inspired me to try to get them
working... and I am rather out of my depth.
The only electrical part (the AC induction motor that powers the
mechanism) works fine in both, but both have other, mechanical issues.
I've run them some under electrical power and spent a lot more time slowly
turning the mechanism by hand, trying to work out what it's doing.
Both have 'sticky digits', i.e. the mechanism that both rotates the type
wheels into the correct position during the print part of the cycle and
then is added to the accumulator in the accumulate part of the cycle
doesn't move freely and thus doesn't print and doesn't accumulate the
correct totals. One also has sticky pins in the input register and the
other doesn't seem to carry at all and has a sticky 'leading zero
suppression' mechanism.
First and foremost, the oil in both machines has congealed into a sticky
mess. I clearly need to replace it, but I have no idea what to replace it
with. I suspect that it's something similar to what's used to lube
typewriters, given that they were built by typewriter companies using
typewriter-inspired mechanisms?
THis is a common problem with all old machinery of this type (including
typewriters, printers, etc). The correct thing to do IMHO is to strip the
thing down and clean all the parts separately. There's a 'butcher's
trick' whcih involves removing the motor (and anything else that might be
damaged) and dunking th whole thing a in a bath of petrol or simialr. It
rrely does much good...
Second, I have no idea how to take them apart correctly. I've successfully
gotten the covers off, but I can't even get the ribbon holder/winding
assembly off since it's linked to a mechanism that's supposed to lift it
to switch from black to red ink, and I can't find a way to safely
disengage them... I've also tried to remove the platen cylinder, but the
ribbon holder is in the way of the retaining screws. The only other things
I can obviously remove at this point are return springs that hold various
levers/cams in place, but I can't see how that would help me remove
anything behind them, and all of the cams seem to be maually aligned on
their axles, held in the correct position by the same screws that would
need to be removed to take the axles out. Ease of service does not seem to
have been a design goal in these machines :-/
The serive manual would be very useful, but I'll but it's totally
unobtainable....
The only thing you can do is 'tread carefully;. My guess, based on
simailar machines, is that they will break down into modules, but you may
have to remvoe other small parts first. You may have to remveo individau
lcams, and they may be adustable (try to mark their postionions bfore
taking them off, I guess the service manual would have the adjustment
procedure, but if oyu had tht you'd not be asking).
My inability to disassemble them is doubly problematic since parts of the
mechanism are buried behind so much other stuff that I can't see what
they're doing, and there are parts that I can't seem to get to move using
any combination of front panel inputs... there's one bit that I've found a
way to reset (subtracting) but not a way to set using normal inputs... and
Subtracting automatically (that is, not manually) could be part of a
division mechanism?
I don't see any way of actuating the
ink-color-swithcing mechanism.
Does anyone have experience with anything similar that would be able to
offer advice? I'd be glad to make photos and my reverse-engineering notes
available...
They are fascinating machines (the whole accumulator rotates around
backwards to subtract!), but I am afraid of damaging them with my clumsy
attempts at repair. Since I have two, I guess I can muddle along by trial
and error, but I would really love to hear from someone that's worked on a
similar device before.
It's almost imposisble to help you without seeign the machines (and I
don't mean seeing pictures of them), but I had a mis-spent childhood
rpairing things (inclduing doing a full ASR33 strip and rebuild without
any manuals). The tricks are to keep notes of what goes where, maybe take
photos as you go along(if you have a digital camera), and to keep
associated parts togethter (so you know where sprigns go, etc). Don't
force anything.
My guess it that you're starting in the right place, and that the ribbon
drive comes off early on. Are you sure the linkage can't be separated?
-tony