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Para.
1
Performance
tests
2
Servicing
guide
3
Fuses
6
Access to components
7
Opening
the oscillator chassis
Chapter 5
MAINTENANCE
CONTENTS
9
Opening
the monitored attenuator chassis
14
Mains transformer
connections
17
Working voltages
18
Presets -
Oscillator
l 9
Resistor R V1
21
Resistor R
V3
23
Resistor RV4
24
Resistor R
V5
26
Resistors R
VB
to R V19
27
Presets - Voltmeter
Table
1
Working
voltages
Fig.
1
Opening the oscillator
chassis
PERFORMANCE TESTS
H
52005-301D
Page
4
2
1.
Test
procedures described
in this chapter may be simplified and of restricted
range
compared with
those that
relate
to
the
generally
more comprehensive factory
test
facilities
which
are necessary
to
demonstrate
complete
compliance
with the specifications. Perform-
ance
limits quoted
are for guidance and should not be taken
as
guaranteed performance
specifications
unless
they are also quoted in
the
Performance Data in Chap.
1.
When
making
tests to
verify that the
instrument
meets the stated performance
limits,
allowance
must
always
be made
for
the
uncertainty
of
the test equipment used.
SERVICING
GUIDE
2.
Maintenance
is
not to be
under taken
except by authorized personnel.
Before
attempting
any
maintenance
the information given should be read with reference
to the
preceding
Techni-
cal Description
chapter.
CAUTION
Fuses
Semi-conductor
de
vices are
used
throughout
the
instrument, and although these
have
inherent
long
term
reliability
and
mechanical ruggedness, they are susceptible
to
damage
by over-loading,
r eversed
polarity
a
nd
excessive
heat
or radiation.
Avoid
hazards
such as prolonged soldering,
strong r. f.
fields or other
forms
of
radiation,
the use
of
insulation
testers or
accidentally
applied short circuits.
3.
The circuits of
the
oscillators
are
protected by three
fuses,
FS1 and FS3
in
series
with
each supply
input connecti
on
to the mains transformer and FS2 in
series
with the centre
tap
of
the
secondary
of th
e
mains
transformer or i
n
series w
ith
the
positiv
e
input
from
a
battery, depending
on
the setting of the BATTERY/MAINS
switch
S2.
Nov. 79
Chap
.
5
Page
1
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