2548H INSTRUCTION MANUAL
56-101-00420 Rev. C
Ch. 3
Nov
/
07
/
14
Page 13 of 33
2. PRELIMINARY
The user should be familiar with the 2548H Fuel Quantity Test Set and its accessory lead
package. The tests and procedures performed are dictated by requirements of the
particular fuel quantity system. System components should be tested and their reliability
verified before attempting calibration.
Refer to the aircraft and/or system manufacturer’s
maintenance manual for specific procedures and calibration values.
A. Battery Installation/Replacement
Before battery installation, test each battery individually to ensure each battery is at peak
load power.
(1) Remove the two (2) screws from the battery holder assembly.
(2) Lift, disconnect, and remove the battery holder assembly. (This aids installation.)
(3) Observe polarity. Install the batteries and ensure the contacts mate.
(4) Reconnect the battery plug.
(5) Replace the battery holder assembly. Secure with the two (2) screws.
B. Battery Test Procedure
(1) Set the Test Set’s ON/OFF switch to ON.
(2) Rotate the Test Set's TEST FUNCTION selector switch to CAP BRIDGE.
(3) Press the BATT TEST pushbutton. Ensure the meter pointer deflection is beyond
the BAT. OK radial line.
Note: Fresh batteries cause an 1100 measurement on the microamps scale. A reading
of 880 µA or greater ensures the best calibration. If the reading is not
acceptable, replace with fresh batteries that test at peak load power.
(4) Release the BATT TEST pushbutton.
C. AC Power Supply Installation/Removal
(If applicable)
Caution: The 115 VAC 50-400 Hz or 230 VAC 50-400 Hz power supplies are meant
for extended use at bench level maintenance. Operation onboard the aircraft
may introduce unintended ground loops that could invalidate the test results.
For this reason and because the power supplies
CANNOT
be used in the
SIMULATION portion of the procedures due to grounding requirements, the
manufacturer
DOES NOT
recommend these power supplies be used
onboard the aircraft.
(1) Remove the two (2) screws from the Battery Holder Assembly.
(2) Lift, disconnect, and remove the Battery Holder Assembly.
