5.
NOTE: The resistance is the meter reading multiplied by the
____
multiplier switch setting.
(b) Measure the resistance between pin 4 and pin 1 on the fuel pump electrical connector (Fig. 601, View B).
NOTE: If the pump resistance is very high, the megohmmeter
____ value will increase with time. For any resistance over 100 megohms it is not necessary to get the actual resistance value. Stop the measurement once the megohmmeter value is more than 100 megohms. Record the measurement on the data sheet as >100 megohms.
(c)
Record the resistance measured between pin 4 and pin 1 on the 757 Fuel Pump Inspection Data Sheet (Fig. 602).
(d)
Set the function switch to the DISCHARGE position.
(e)
Do these steps again to measure the resistance between pin 4 and the remaining pins on the fuel pump connector, pins 2 and
3.
(f)
Put the power switch to the OFF position and remove the test probes.
S 766-067
(3)
Make an analysis of the test results:
(a)
If any resistance measured between pin 4 and pins 1, 2 and 3 is less than 1 megohms, do these steps: 1) Replace the applicable fuel pump (AMM 28-22-03/401). 2) Do the Continuity/Resistance Check on the new fuel pump.
a) Start with this procedure: Fuel Pump Continuity Check.
(b)
If any resistance measured between pin 4 and pins 1, 2 and 3 is equal to 1 to 5 megohms, replacement of the fuel pump is optional. Boeing recommends that the fuel pump be replaced. 1) If the fuel pump is replaced, do these steps:
a) Replace the applicable fuel pump (AMM 28-22-03/401).
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MAINTENANCE MANUAL
b) Do the Continuity/Resistance Check on the new fuel pump (Start with this procedure: Fuel Pump Continuity Check).
2) If the fuel pump is not replaced, the insulation resistance test must be done on that fuel pump every "A Check", or an equivalent time.
NOTE: Do the checks of the fuel pumps at the maintenance
____ interval in SB 757-28A0043, Revision 1 (every A-check or an equivalent time).
(c) If each resistance measured between pin 4 and pins 1, 2 and 3 is equal to or more than 5 megohms, the fuel pump resistance check is satisfactory. 1) If the insulation check is satisfactory, do these steps:
a) If the fuel boost pump was removed for the test, re-install the boost pump unit.
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