Omega Vehicle Security 450 - Manual (Page 26)

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at the “-1.23V” testpoint: disregarding
polarity indication, record the voltage.
f. Move the DVM HI lead to the “3.7V”
testpoint and record the voltage (disregard
polarity).
g. The voltage measured at the “3.7V” test-
point should be 3.007 times larger than
the voltage measured at the “-1.23V” test-
point. Adjust Rc (which varies the +3.7V
line to attain the proper ratio.
h. Adjust Rb for an indicator display of 0.2
°
C.
i. Set the resistance box to 148.4 ohms.
j. Adjust Ra for an indicator display of +101.0
°
C.
k. Reassemble the indicator.
l. Perform the zero calibration