Copyright PSC
2000781K MkII MLB Operating Procedure
Page 44 of 68
Step
Procedure
Date & Initials
Tech.
QA
9.3.9
Disconnect the
SFF Power and Measurement Circuit
from the Lightband’s
DB-9 socket connector in Figure 9-3.
9.3.10
Measure resistance directly at the Lightband's DB-9 socket connector and
complete Table 9-2. Contact PSC if a discrepancy is found.
PSC recommends using a DMM. It will not cause damage to or operate the
Lightband. If using a milliohm meter (four wire Kelvin probe system) ensure
the test current is <0.01 A to prevent rotating the motors.
See Figure 13-1 for the Set-For-Flight Motor Bracket Assembly switch state.
Note: ensure the mating DB-9 pin connector is visibly clean to prevent
contaminating the Lightband’s socket connector.
Table 9-2: Set-For-Flight resistance measurements (values apply only at NTP)
Lightband State
Object Being Measured
Pin
Connections
Resistance [
Ω]
Allowable (1)
Measured
Set-For-Flight
Motor A
2 , 4
8.0 to 11.0
Motor B
6 , 8
8.0 to 11.0
Deploy Limit Switch A
1 , 2
< 0.3
Deploy Limit Switch B
5 , 6
< 0.3
Stow Limit Switch A
3 , 4
> 1E7
Stow Limit Switch B
7 , 8
> 1E7
Stow Limit Switch A
4 , 9
< 0.3
Stow Limit Switch B
8 , 9
< 0.3
Motor A Deploy Circuit
1 , 4
8.0 to 11.0
Motor B Deploy Circuit
5 , 8
8.0 to 11.0
(1) Ensure the over limit (OL) indication on the resistance measurement device complies with the
maximum tolerance. This is the case for the DMM referenced in Table 2-5.
