Rotate System Without Adjustable Balance Arm

 

When the balance arm adjustment was eliminated, it became necessary for a change in the rotate a~justment procedure for those machines.

 

Having the knowledge of two methods of adjusting the rotate system is always a benefit to the technician.

 

It is possible to use this procedure on IBM Typewriters that have the adjustable balance arm.In order to use this procedure on the earlier machines that still have the compensation arm, you must;

 

 1. Cripple the rotate arm, using the procedure in the IBM Manual.

 

 2. Preset the adjustable balance arm so the inner arm aligns to the left by half the width of the notch in the outer arms as shown in figure 143.

 

 3. Preset the negative 5 (-5) stop screw with the cycle shaft at rest. Adjust the screw until it contacts the stop - then backoff 1/2 turn. Rotate the cycle shaft and check both sides of the -5 cam to be sure the -5 latch drops over the screw.

 

 4. Adjust the rotate arm, with the turnbuckle (123-16) to the #1 scribe line on hooverometer. Because the IBM Selectric III typewriters have a different cut on the negative cam to give it 6 units of motion, the rotate arm should be preset 1 unit more positive to prevent interference. One way to approximate this adjustment is to divide the distance between position 1 and position 2 on the hooverometer into 5 increments. Then adjust the rotate arm to the 1st increment past the #1 mark.