User's - Datron 1062 Service Handbook

51
SECTION
4
INTERNAL
ADJUSTMENT PROCEDURES
4.1
ALTERATtON OF
LINE
VOLTAGE
AND
LINE
FREQUENCY
The
instrument
is
set to
50Hz,
205V
to
255V
supplies unless
Option 80, 81
or
82
is
specified.
This
information
is
carried
on
the
instrument identification
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
link(s)
connecting the
split
primary on
the
prirrted
circuit
board
in
front
of
the toroidal
line
transformer.
Fig.
2.1
and Drawing
No
400295.
4.
115V
Operation:—
Remove LK1
(link
Hand
fit
LK2
and LK3'
'
230V
Operation;—
Remove
links
LK2
and LK3, and
fit
LKl(').
5.
Amend
instrument identification label.
6.
Replace lower cover.
7.
Replace power
fuses with
160mA
anti-surge
(230V)
or
500mA
anti-surge
(115V).
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.
400Hz
Operation:—
Remove
link
LK5
and
fit
LK?f^J
on
the Digital
assembly, (Drawing No.
400329).
50/60HZ
Operation:--
remove
link
LK7
and
fit
LKSt^^ on
the Digital
assembly (Drawing No.
400329).
4.
Place
instrument
into
HOLD.
Adjust
L2
(Digital
assembly)
so that
TP7
is
1.05V
±0.03V
with
respect
to
Digital
Common
(TP28).
NOTE:
This
signal
contains
about
200mV
peak-to-peak
high frequency
noise.
5.
Amend
instrument identification
label.
6.
Replace the top cover.
7.
Carry out the Specification Verification
tests
(Sec-
tion
8,
User's
Handbook) and
recalibrate
if
necessary.
Links should be 22
SWG
TIN.Cu
wire with
silicone
rubber
sleeving.
4.2
BATTERY REPLACEMENT
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.
1.
Remove top cover and
locate battery
on
the Digital
assembly
(see Fig. 2.1
).
2.
Power-up instrument.
3.
Desolder battery
at
end of
tags
and remove from
clip.
4.
Replace with
new
battery,
(Datron Part
No. 920049)
positive
terminal to resistor.
5.
Replace top cover.
6.
Amend
instrument identification label
(Current date
-t-
5
years).
7.
Carry out the Specification Verification
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
certain
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
important,
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
Q12
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
instrument. Personal contact with these points
may
result
in
injury.