WARNING:  MAKE SURE ALL PERSONNEL AND OBSTRUCTIONS ARE CLEAR OF AILERON, ELEVATOR AND TAB SURFACES. SURFACES MAY MOVE ABRUPTLY WHEN HYDRAULIC POWER IS APPLIED.

(4)  
Ensure elevators are operable.

(5)  
Ensure autopilot circuit breakers are closed.

C.  Test Pitch Force Transducers
(1)  
Connect spring scale to center hub of captain's control column.

(2)  
Engage autopilot A to CWS. Observe CWS ROLL and CWS PITCH is annunciated.

NOTE: If force transducers are not adjusted properly, autopilot may not engage.

(3)  
Slowly push on the captain's column until the column starts to drive. It should require 4.5 to 8.5 pounds. Record value.

(4)  
Repeat step (3) except pull on column. Recorded values should differ by less than 2 pounds.

(5)  
Repeat steps (3) and (4) using first officer's column.

(6)  
Place autopilot A to CMD and select altitude hold mode and repeat steps (3) thru (5) except apply a steady pull on control column until altitude hold mode returns to off. Check that pull required is between 18 and 24 pounds. Disengage autopilot.

(7)  
Repeat previous steps using autopilot B channel.

D.  Restore Airplane to Normal Configuration
(1)  
Remove spring scale from control wheel.

(2)  
Remove electrical and hydraulic power, if no longer required.

580 
22-11-92 Page 506  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Feb 20/86 

STABILIZER TRIM POTENTIOMETER - REMOVAL/INSTALLATION
EFFECTIVITY
SA ZS-SBL thru ZS-SBR GJ ALL EXCEPT B-2509 and B-2510
1.  General
A.  Stabilizer trim potentiometer is mounted above the feel computer, next to the stabilizer jackscrew (Fig. 401).
2.  Remove Stabilizer Trim Potentiometer
A.  Remove access door 3701 (Ref Chapter 12 Access Doors and Panels).
B.  Remove electrical connector from potentiometer.
C.  Loosen nut on potentiometer crank bolt and remove crank from potentiometer shaft (Fig. 401).
D.  Loosen two screws in clamp and remove potentiometer.
3.  Install Stabilizer Trim Potentiometer
A.  
Set horizontal stabilizer at 0 degree, equal to B dimension of 41.57 士0.01 inches (Ref
Chapter 27 Horizontal Stabilizer Trim Control System).

B.  
Align index marks on potentiometer housing and shaft.

C.  
Install potentiometer with index mark in vertical position pointing upward.

D.  
Tighten two screws in clamp to 40 to 50 pound-inches torque (Fig. 401).

E.  
Without disturbing position of potentiometer, install crank on potentiometer shaft.

CAUTION:  ENSURE THAT THE POTENTIOMETER CRANK IS CORRECTLY ORIENTED AS SHOWN IN FIG. 401 FOR PROPER AUTO STABILIZER TRIM OPERATION. DAMAGE TO CRANK COULD RESULT IF INSTALLED IN AN INCORRECT ORIENTATION.
F.  Tighten nut on potentiometer crank bolt to 12 to 20 pound-inches torque.
G.  Adjust potentiometer (Ref Stabilizer Trim Potentiometer - Adjustment/Test).
H.  Check operation of stabilizer trim potentiometer.
I.  Replace access door.
Oct 20/87 22-11-101 Page 401
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

H29050
Stabilizer Trim Potentiometer Installation  500 
22-11-101Page 402   Figure 401 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Aug 15/67 

STABILIZER TRIM POTENTIOMETER - ADJUSTMENT/TEST
EFFECTIVITY
SA ZS-SBL thru ZS-SBR WA N4502W-N4571M GJ ALL EXCEPT B-2509 and B-2510
1.  Stabilizer Trim Potentiometer Adjustment
A.  Equipment and Materials
(1)  
Test Receptacle - MS24266R14B15S6, with insulated test leads from pins 5 and 6

(2)  
Rigging Pin E3 - 0.309 +0.003/-0.000-inch diameter (MS20392-4)

(3)  
Wheatstone Bridge - Model 5430-A, Leeds and Northrup

B.  Adjust Stabilizer Trim Potentiometer
(1)  
Remove access door 3701 (Ref Chapter 12, Access Doors and Panels).

(2)  
Set horizontal stabilizer at 0 degree, equal to B dimension of 41.57 士0.01 inches (Ref Chapter 27, Horizontal Stabilizer Trim Control System).

(3)  
Install rigging pin E3 (Fig. 501).

(4)  
Disconnect electrical receptacle and install test receptacle on trim potentiometer.

(5)  
Connect Wheatstone bridge to test leads.

(6)  
Measure resistance with respect to zero index resistance stamped on potentiometer nameplate. Check that deviation is less than 士10 ohms. If deviation is less than 士40 ohms, adjust per step (a). If deviation is greater than 士40 ohms, adjust per step (b).
　
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