Reading MT/ST Tapes

On 2021-07-31 1:19 p.m., Chuck Guzis via cctalk wrote: I have never seen either of these machines but looking at pictures of them it looks like the first version of 1620 had a type bar typewriter as a console.? These type bar machine would have a common heritage with the Flexowriters both are descendants of the? Electromatic company that IBM purchased in 1932 but later sold off what became Flexowriter due to anti-trust concerns. I did find a picture of a 1620 that does appear to have a selectric for a console and it looks like it is a modified OP selectric even being in the same case sunk into the desk so I suspect that it is the first version of the selectric I/O. The console on the 1130 does however look like it is a 1052 that has been integrated into the machine. Speaking of shaking apart on carriage return, I was once preparing some cash registers for the local phone company in a room where the had a HP mini that apparent ran some terminals for their subsidiary phone company in Prince Edward Island.? This HP had an ASR-33 for a console and it seemed that it printed a line for every transaction and when it would return it would slam into the dashpot on the left frame and the whole ASR-33 would rock. This mini recorded transactions on punched tape that was taken downstairs to the main computer room where it was read into the IBM mainframe on a high speed punched tape reader that looked like a 3430? tape drive with the magnet head replaced by an optical head. With regard to the position of the belt it is where it is because the selectric mechanism is split into two parts. On the left is the cycle shaft with the cams that position the type ball and through some gears turns the print shaft that drives the ball into the paper.? right in the middle running inside the appropriately named center bearing, is the hub that has the pulley on it that is driven by the motor this turn constantly.? on the left side of the the hub there is a torrington clutch? that when tripped turns the cycle shaft to print a character.? On the right side of the hub is the operational shaft that turns all the time that have clutched cams on it to operate functions such as tab and backspace, plus another torrington clutch for carriage return, and on the extreme right a cam for shift that rotate the ball 180 degrees.? It would seem that the motor belt is positioned where it is so that the entire machine could be operated from a single motor. On OP selectrics changing the belt is not such a big deal, you take out one of the gears that drives print shaft, remove the screws that hold the bearing plate on the left end of the cycle shaft and the either back off or remove entirely the cycle shaft. It was more of a challenge on the original I/O because of the presence of contact block both at the end of the cycle shaft and under the selection latches.? The original I/O was just a modified OP selectric That other than the addition of the contacts and magnets the only other change was the beefier capacitive start motor, I have seen this motor tear the teeth off a belt on a jammed machine just by turning it on.? You did not even have to look to tell if a belt was missing teeth, they had a telltale thumping noise you could hear as soon as you got close to it. The I/O II was a lot better changing belts was pretty much the same? as an OP selectric and I don't recall having to change them as often.? The worst where the machines that where in a case like an OP selectric sunk into a desk, that case and mount just made things more difficult. Part of the fun of the banking terminals was some bank branches had the machines on the counter, right where the banks customers are, and customers would often feel obliged to offer some of their wit or wisdom while you where up to you elbows in a greasy machine.? I those days of working on greasy mechanical machine we where obliged to wear suit and tie, but greasy machines where not the worst, for that there was proof machines with their purple indelible ink used to print endorsement stamps on documents. After working on them you would have purple hands for a few days. Paul.