On 2023-01-29 12:25 a.m., Chuck Guzis via cctalk wrote:
On 1/28/23 20:20, Paul Berger via cctalk wrote:
The keyboard on a 1052 is a keypunch keyboard I believe it is the same
as the 029. The printer in the 1052 is a keyboardless Selectric with no
tab rack and they spaced via a cam on the OP shaft instead of taking a
cycle. The ones I saw on a couple 360s (22 and 25) the space cam was so
worn it wobbled when it took a cycle, but the customer would never let
us do anything with it as long as it worked because they could not do
anything with out the console.
Was the 1052 more or less durable than the model B adapted for the 1620?
With its movable carriage, it always seemed to be in danger of
self-destructing--the thing would shake a bit then a carriage return was
executed.
--Chuck
My experience is that they where pretty durable, I never saw a lot of
1052s by the time I started in 1979 there was not a lot of 360s in our
branch. I think they did pretty good given that they are the same
mechanism as the OP selectric the only thing different in the printer of
the 1052 and also the early selectric terminals, was the 1052 and
terminals had a capacitor start motor that was stronger than motor in
the OP selectric, strong enough that if the mechanism did jam it could
tear the teeth off of the motor belt. A 1052 would hammer away pretty
constantly printing out the console log, and since it did not have a tab
rack, it used spaces to line up the columns on the printout, which is
likely why the space clutch and cam where in such bad shape.
I don't know how they would compare to a model B that was used as an I/O
I never saw any systems that used one. I would imagine that moving the
heavy carriage back on something that is printing steady would be a
trouble spot. I would image that kind of use would also be hard on the
power roll that drives the type hammers into the paper. I don't image
they would be very fast, a Selectric could print at 15.5 characters per
second and at that speed the cycle clutch never latched it was just one
continuous cycle. Selectric I/Os that ran at full 15.5 chars/sec
suffered way more problems than ones that printed at a lower speed.
IBM later came out with a second Selectric I/O which had the high wear
parts beefed up in them and the keyboard was separated from the printer.
All of the open transfer contacts where replaced by reed switches and
magnets. The filter shaft was driven by a clutched gear running off the
OP shaft and magnets against the bails under the keyboard moved magnets
to select the character code but I don't recall how it was strobed, but
I seem to recall that it was another magnet that was always moved by the
filter shaft but was a little behind the magnets for the character
reeds. These I/O II units where a lot more robust.
Paul.
