51
sEcTtoN 4
INTE RNAL
ADJUSTMENT
PROCEDUR
ES
4.1
ALTERATTON
OF
LINE
VOLTAGE
AND
LINE
4.2
BATTERY
REPLACEMENT
FREOUENCY
2,
3.
4.
5.
6.
7.
t
ir I
iiI
.u
The
instrument
¡s
set
to
50H2,
205V
to
255V
supplies
unless
Option
80. 81
or
82
is
specified.
This
information
is
carried
on
the
¡nstrument
identif
ication
label
located
on
the
rear
panel.
Alteration
to
a
different
line
voltage/line
frequency
may
necessitate
an
instrument
recalibration.
4.1.1
Changing
Line
Voltage
1.
Disconnect
power
and all signal
input/output
leads.
2.
Remove
the lower
cover.
3.
Locate
the l¡nk(s)
connecting the
split
primary
on
the
printed
circuit
board
in front of the toroidal
line
transformer',
Fig.
2.1
and Drawing
No 400291
4.
t
t:X."ff!111n:-
Bemove LKI
(link
1) and
f it
LK2
230V
Operation:-
Remove
links
LK2 and LK3, and
1¡1
¡ç1
[1J
.
5.
Amend instrument identif
ication
label.
6. Replace lower
cover.
7.
Replace
power
fuses
with 160mA
anti-surge
(230V1
or
500m4 anti-surge
(1
15V).
8. Carry
out
the
Specification Verification
tests
(Sec-
tion
8, User's Handbook) and recalibrate
if necessary.
4.1.2
Changing Line
Frequency
1.
Disconnect
power
and all signal input/output
leads.
2. Remove
the top cover.
3.
4OOHz
-Operation:-
Remove link
LK5
and fit
¡¡7[1]
on the Digital assembly,
(Drawing
No.
400329).
50/60H1
-Operation:-
remove link
LK7
and fit
¡¡5t1.|
on
the Digital assembly
(Drawing
No.
400329).
4. Place
instrument
into
HOLD.
Adjust
L2
(DiSital
assembly)
so
that
Tp7 is l.OSV
f.0.03V
wirh
respect
to Digital
Common
(Tp2g).
NOTE:
ïhis
signal
contains
about 200mV
peak-to-peak
high frequency
noise.
5.
Amend instrument
identif
ication label.
6.
Replace the
top
cover.
7.
Carry
out the
Specif
ication
Verif
ication
tests
(Sec-
tion
8,
User's Handbook)
and
recalibrate
if necessary.
[1]tinL,
should be
22
SWG
TlN.Cu
wire
with
silicone
rubber
sleeving.
The battery
should be
replaced on
or before
the
date indicated
on the rear
panel
instrument
identification
label.
To retain
the calibration
memory, the
instrument
must be
powered-up
during replacement. Therefore
great
care must
be
taken
due
to voltages up to 260
volts being
present
inside
the instrument.
Remove
top cover and
locate battery on the
Digital
assembly
(see
Fig.
2.1).
Power-up
instrument,
Desolder
battery at end
of tags and remove from
clip.
Replace with new
battery,
(Datron
Part
No.920049)
positive
terminal to resistor.
Replace
top cover.
Amend instrument
identification
label
(Current
date
+
5
years).
Carry
out
the
Specification
Verificat¡on
tests
(Sec-
tion
8, User's Handbook)
and recalibrate
if
necessary.
4.3
POST.REPAIR
PROCEDURES
Apart
from the RMS Module
(which
is available
only
from
Datron),
all integrated circuits and
semiconductor
devices are
standard manufacturers'
products,
and
special
selection
is
unnecessary.
During manufacture
ærtain
resistors
are selected
in value
(FSV
=
Factory
Selected
Value)
to accommodate
circuit component tolerances,
or
to
bring the
desired
setting of
a
preset
control
to the
middle of its adjustment
range.
The thermal
tracking of
the DC Preamplifier
is
part-
icularly
¡mportant,
to
ensure
a low
order
of
zero
drift
with variations
of
temperature. This
rather
time consum-
ing
procedure
is carried out
initially
during manufacture,
and
need
only
be repeated
following
replacement
of O12
or
any component
associated
with
the
temperature
com-
pensation
circuitry.
NOTE:
A
routine calibration
as detailed in
Section
1 should
be
carried out
after
completion
of the following
procedures.
CAUTION
:
Up
to 260
volts is
present
inside
the
¡nstrument. Personal
contact
with
these
points
may result
in
injury.
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