5-8. COMPUTER ALIGNMENT
General. Computer test set TS-909/PPM is the only item of test equipment required to align the computer.
Instructions for operating the test set are contained in TM 11-1223.
(1) Connect the power cable of the test set to receptacle J898, located underneath the computer drawer.
(2) Connect the black ground lead W4605 of the test set to a good ground in the computer drawer.
(3) Adjust the gain potentiometers on all eight servoamplifiers fully clockwise. After adjusting each
potentiometer to its clockwise limit, check the associated gear train for chatter and hunting. If gear chatter
exists, turn the adjusting potentiometer slowly counterclockwise until the chatter stops. On amplifier
AR927A, check the C subassembly dials for proper torque at range setting of 2, 000 meters, with a
minimum of chatter for a range setting of 10, 000 meters. If some compromise is necessary in this
adjustment, a slight chatter at 10, 000 meters is preferable to a lack of torque at 2, 000 meters.
(4) Set the beam separation dial on R822 to 35 mils.
Note: Each adjustment potentiometer in the computer is locked by a locknut on the potentiometer shaft.
To adjust the potentiometers, first loosen the locknut. After the adjustment has been made, hold the shaft in
position while tightening the locknut, observing the null meter of the TS-909. Only after each adjustment is
locked into the correct adjustment should you proceed to the next adjustment.
(5) Set RADAR LOCATION EASTING and NORTHING counters to. 000000.
Set time to zero.
Black lead to J897.
Red lead to J890.
Coax lead to J871.
Bridge to 0000.
Meter should null; if not, adjust R801.
Single beam-dual beam switch to dual beam position.
Alignment of the Height Subassembly.
(1) Connect the red test lead to J890.
(2) Connect the black test lead to J897.