HP 437B Service Manual

HP 437B
Equipment
Procedure
5-10
Note
ADJUSTMENTS
Test Power Meter......0 0.0. c cece cece tee eeaeeeeeeeeeneens HP 432A
Thermistor Mount...........cc ccc cece cee cececceeveeuceseugeees HP 478A-H75
Digital Voltmeter (DVM)...... 0.0.0... cece ev cceccceeaeacuceeneneuegs HP 3456A
1. Set up the DVM to measure resistance. Connect the DVM between the
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9.
10.
Vrf connector on the rear panel of the test power meter and pin | on
the thermistor mount end of the test power meter interconnect cable.
Round off the DVM indication to two decimal places and record this
value as the internal bridge resistance (R) of the test power meter
(approximately 200 ohms).
R (Internal Bridge Resistance)
Connect the test power meter to the Power Meter as shown in Figure
5-4.
Set the Power Meter LINE switch to ON. Ensure that the PWR REF is
off. Wait thirty minutes for the test power meter thermistor mount to
stabilize before proceeding to the next step.
4
Set the test power meter range switch to coarse zero and adjust the @
front panel coarse zero control to obtain a zero meter indication.
Fine zero the test power meter on the most sensitive range, then set the
power meter range switch to 1 mW.
rT) Ensure that the DVM input leads are isolated from chassis ground when
oF performing the next step.
Set up the DVM to measure microvolts.
Connect the positive and negative input leads, respectively, to the
Vcomp and Vrf connectors on the rear panel of the test power meter.
Observe the indication on the DVM. If less than 400 microvolts, proceed
with the next step. If 400 microvolts or greater, press and hold the test
power meter fine zero switch and adjust the coarse zero control so that
the DVM indicates 200 microvolts or less. Then release the fine zero
switch and proceed to the next step.
Round off the DVM indication to the nearest microvolt and record this
value as VO.
vw

HP 437B Specifications

General

Brand	HP
Model	437B
Category	Measuring Instruments
Language	English