C. Provide external electrical (Ref 24-22-0 MP).
(1) Place battery switch to ON.
D. Check that parking brake is set.
E. Check that ground interconnect valve is in CLOSED position.
3. Hydraulic System B Trouble Shooting Chart
NOTE: Pump high and low pressure adjustments are made on a test bench before pump installation. Pump pressure adjustments should not be attempted while the pump is installed on the airplane because of the internal bleed characteristics of the hydraulic system. Pump pressure adjustments are made under zero flow conditions.
If electrical power to a hydraulic pump has been interrupted during normal operation by the ground fault protection system, the pump should be replaced (Ref 29-12-21 R/I).
If pump will not operate after replacement or after repair of the electrical circuit, check that reset button is RESET on ground fault protection controller located aft of P6-1 circuit breaker panel. If pump still will not operate, perform ground fault protection test (Ref 29-12-21 A/T).
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29-12-0 Page 102 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Jan 20/82
TROUBLE PROBABLE CAUSE ISOLATION PROCEDURE REMEDY
Pressure above normal (3100 psi) Overheat warning light illuminates. (Temperature above 220°F accompanied with pressure above 3100 psi) Hydraulic pressure indicator and/or transmitter Electric pump or pumps Case drain or pressure filter contaminated Open ground interconnect valve and pressurize system A. Compare system A and B indicator readings. If system A indicator reads normal and system B indicator still reads high, then system B transmitter and/or indicator are defective If both system A and system B indicators read the same then one or both system B pumps are defective. Close interconnect valve Operate both system B pumps. Switch No. 1 pump OFF and record reading on indicator. Switch No. 1 pump ON and switch No. 2 pump OFF and record reading on indicator. Compare readings of two pumps If difference is noted then high reading pump is above tolerance If no difference is noted then both pumps are above tolerance Check applicable pump case drain and pressure filter for contamination Test pressure indicator and transmitter. Calibrate or replace as required. Refer to 29-31-0, Pressure Indicating Systems Remove applicable pump for bench test and repair Remove both pumps for bench test and repair If contamination is found, refer to 29-12-0/601, to check hydraulic system B filters. Replace filter elements and recheck system.
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Feb 01/96 29-12-0
Page 103
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
TROUBLE PROBABLE CAUSE ISOLATION PROCEDURE REMEDY
Pressure below tolerance specified in par. 1.C. Hydraulic pressure indicator and/or transmitter System B electric motor driven pumps No. 1 and No. 2 Hydraulic leak Open ground interconnect valve and pressurize both system A and B with system pumps. Compare system A and system B pressure indicator readings If system A indicator reads normal and system B indicator still reads below normal then system B transmitter and/or indicator are defective Pressurize system with hydraulic ground service cart. With ground interconnect valve open and both system A and B indicators reading normal, then both system B pumps are defective Pressurize systems A and B. Monitor fluid quantity indicators and reservoir low level warning lights If quantity indicator indicates losing fluid, shut down hydraulic system, open panels and trace hydraulic fluid leakage to its source NOTE: Approximately 2.0 gallons of fluid will drain from system A reservoir to system B through balance line. Therefore system A reservoir-quantity indicator will drop Test system B pressure indicator and transmitter. Repair or replace as required. Refer to 29-31-0, Pressure Indicating Systems Replace system B electric motor-driven pumps No. 1 and No. 2 Repair or replace defective components
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