Motor power test of the 1053 functionality - first session

TEST RIG SET UP

I won't use the IBM 1130 for this early test. I built a breadboard test rig with a timer to apply a proper duration pulse of +48V while grounding chosen solenoids so that they fire together when the timer emits its pulse. The timer drives a relay that connects the +48V to the high side of all the 1053 solenoids. 

I use a breadboard connected to a bank of relays that connect the solenoid end to ground. By plugging selected relays to +5, they are energized to switch ground to the associated solenoids of the typewriter. Thus, I move jumper wires to select the solenoid or solenoids I want to fire, then push a button on the unit hosting the timer and it cycles the relays to activate the 1053. 

AC POWER APPLIED TO TYPEWRITER MOTOR

The motor of the 1053 is wired to 115VAC and runs continuously. It turns the operational shaft steadily. The clutches on the shaft are what couple the motor to the rest of the typewriter. 

The print cycle clutch couples the motor to turn the print shaft and related parts for selecting one character on the type ball and hammering it against the ribbon and paper. The two operational clutches activate movement functions such as space, tab and carrier return. The return clutch couples the motor to wind the carrier back to the left margin. 

I whipped up an AC cord with a Molex connector to fit into the typewriter so that I could power it without putting AC on the exposed SMS paddle cards on the workbench. 

FRONT PUSHBUTTON FUNCTIONS TESTED

The front of the 1053 has three pushbuttons, marked Tab, Space and Return, which will fire off the relevant movement. I tested each of them, watching for the proper operation. 

I tested Space at the left, middle and right sides of a typed line to be sure it works satisfactorily at all positions. As long as Tab moved the carrier all the way to the next set column, it was good. Finally, Return must bring the carrier back to the column that was set by the left hand margin lever. 

I found that all three triggered their associated functions. The space worked well as did tab. I discovered that carrier return is failing to arm the margin bar at the start of the operation and this in turn stops it from latching on. The return thus stops as soon as the operational clutch cycle that triggers it ends, rather than continuing until the left margin. If I armed the margin bar first, it moved the full distance.

MOVEMENT AND RIBBON FUNCTIONS TESTED

The controller logic can fire five movement functions by energizing solenoids. These are Tab, Backspace, Space, Index and Carrier Return. Three of them are also controlled by the pushbuttons so that it was very likely they would work properly by solenoid activation in addition to the button. The Backspace and Index (line feed) do not have buttons and thus this is the first test of them under power. 

All five of these movement functions trigger and operate correctly (other than the carrier return issue raised above). The ribbon shift to black and shift to red also performed perfectly. 

Space

Backspace

Carrier return

Tabulate

Index

CHECKING PRINT CHARACTERS

I wasn't ready to test that all 88 characters are properly selecting but I did make sure that all the selection magnets will fire and trigger a print cycle - T2, T1, R1, R2, R2A , R5 and AUX. I did a couple of tilt positions and a couple of rotate positions just to see that it was approximately correct. I haven't finished the rotate selection adjustment process yet so I will come back to these tests once the setup is complete. 

Tilt

Rotate

Slow motion

What became apparent was that the print escapement was not working properly. The carrier should move one column to the right at the end of a print cycle, driven by a cam on the print filter shaft, but no movement took place. I will need to adjust this so that it works as reliably as space triggered by the buttons or operational selection magnet. 

SHIFT BETWEEN UPPER AND LOWER CASE HEMISPHERES

The solenoid to drive the 'down shift', e.g. to the lower case side of the ball, worked as expected. However, the solenoid for 'up shift' did not fire off the shift mechanism. I had to fiddle with it manually to shift back to upper case. This needs to be adjusted. 

CONDITION ASSESSMENT

The print escapement does not work when printing characters. The up shift command does not work. The carrier return, regardless of how it is triggered, does not latch to completion because the margin bar is not armed. Outside of these issues, the 1053 was performing to specification. 

Note that I did not test the character selection because I know I have not finished with the rotate selection adjustment process at this time.