HP 8901B Operation And Calibration Manual page 392

Model
8901B
Adjustments
Section
5
ADJUSTMENTS
5-1.
INTRODUCTION
This
section contains adjustments and checks that assure peak performance of
the
iModulation
Analyzer. The instrument should be readjusted after repair or failure to pass a performance test.
Allow a 30 minute warm-up prior to performing the adjustments. Removing the top cover is the
only
disassembly required for most adjustments.
To determine which performance tests and adjustments to perform after a repair, refer
to
paragraph
5-5, Post-Repair Tests, Adjustments, and Checks.
5-2.
SAFETY CONSIDERATIONS
T h i s
section contains information, cautions, and wa-nings which must be followed for
your
protec-
tion and to avoid damage to the equipment.
Adjustments described i n this section are performed with power supplied
to the instrument and with protective covers removed. Maintenance should
be performed only by service trained personnel who are aware
of
the hazard
involved (for example, fire and electrical shock). Where maintenance can be
performed without power applied, the porixr should be removed.
Removal o f the Modulation Analyzer's bottom cover is not necessary to
perform these adjustments. However,
i f
the bottom wver is removed.
hazardous voltage
( ~ 1 2 0
Vac) is nccessiblc.
A
pin-to-pin coltage difference
of
55 V d c may bc found on man?
of
thc
Modulation Analyzer's circuit board conimtors. Be careful while uorking
on the circuit boards with power supplicd to the instrument.
I f a circuit board is placed on uri exteridcr
board,
the possibility
of
coming
in contact uith 55 V d c is greatly increased. Be curefiil while working on
the circuit boords with porcer supplicd. Work uith one hand. DO not toiich
the extendcr board.
5-3.
EQUIPMENT REQUIRED
Each adjustment procedure contains a list
of
required test equipment. The test c;uipment is
identified
by
callouts
in
the test setup diagrams where included.
If substitutions must be made for the specified test equipment, refer to Table 1-3 in t l x Operating
Mcinual
for
the minimum specifications. It is important that the test equipment m e a
the
critical
specifications listed in the table if the Modulation Analyzer is to meet its pciformance riquirements.
5-
1