TM 1-1270-476-30
4-246
4-29. CONTROL PANEL ASSEMBLY 2A1 REPAIR (cont)
12. RESISTOR R3 ADJUSTMENT
a. Connect ohm meter leads between
contacts 2 and 55 of connector J3 (1).
b. Move R3 thumbwheel (2) until
approximately 570 to 630 ohms is read.
NOTE
It may be necessary to loosen setscrews (3)
and reposition thumbwheel (2) to obtain
reading.
c. Loosen thumbwheel setscrews (3). Move
top of thumbwheel (2) toward HOD (4), until
mechanical stop is reached.
d. Tighten either setscrew (3). Only one is
required.
e. Record ohm meter reading.
f. Move ohm meter lead from contact 2 to
contact 3 of connector J3 (1).
g. Move top of thumbwheel (2) away from
HOD (4) to the other mechanical stop.
Record ohm meter reading.
h. Subtract step e ohm meter reading from
step g ohm meter reading.
i.
Divide the difference by 2. Add the result
(positive or negative) to the ohm reading
recorded in step e.
j.
Move ohm meter lead from contact 3 to
contact 2 of connector J3 (1).
k. Move top of thumbwheel (2) toward HOD
(4) until resultant reading from step i is
obtained ±10 ohms.
l.
Loosen setscrew (3) on thumbwheel (2).
Move top of thumbwheel (2) toward the
HOD (4) to the mechanical stop.
m. Tighten both setscrews (3).
n. Record ohm meter reading.
o. Move ohm meter lead from contact 2 to
contact 3 of connector J3 (1). Move top of
thumbwheel (2) away from HOD (4) until
the mechanical stop is reached.
p. If the ohm meter reading is not within 50
ohms of the reading obtained in step n,
repeat steps c through o.
