Philips PM 6302 - Adjusting Procedures

37
3,5.2.
Adjusting
procedures
3.S.2. 1.
Potentiometer
713
—
Check that
the scale
marking coincides
with the
left-hand stop
of the
potentiometer
—
Measure
the resistance at
scale point
1
(R713/1)
and at
scale point 10
{R71 3/10)
Measuring fault
< 1
%
(e.g. with
PHILIPS
PM 2421
digital multimeter)
-
With the
measured
values 713/1 and
713/10
found
above, read
out the
values for
the adjusting
resistors
from
table I
(take always die
next higher
value)
Procedure:
—
Solder a
resistor of the
found value
for 659 into
the circuit.
Replace
resistor 637
by a
resistance decade
adjusted to
the value
found.
—
From table I,
solder
resistor 658 into
the circuit
and
replace resistor
635 by a
resistance
decade also
adjusted
to the
value found.
—
By
alternating
the
adjustment of scale
points 1
and 10 in
range xl
kfi, the
definitive
values for
resistors 635
and
637 can be
determined.
Scale point
1 must be
adjusted
with a sample
of 1 kfi
±1
%.
,
while scale
point 10
must be
adjusted with a
10
k£2
±
1 %»
sample.
3.5.22.
Reference
capacitor
-
From table I
take the
value for R|\|
relevant to the
measured values
of R713/1
and R713/10
—
From table
II take the
values
for capacitors
516 and
517
relevant to the
value
found for
Rn
—
Solder capacitor
516 with
the value
found into
the circuit
—
Replace
capacitor 517 by
a
capacitance decade
adjusted to
the
value found
-
Set range
switch to
position xIO
nF
-
Set
frequency
scale to 10
-
Connect
a sample
of 100
nF
±
1 %.
between sockets
l-E
-
Reduce the
detuning
of the bridge to
a
minimum by
varying
capacitance
517
—
Solder the
selected
capacitor
value into
the circuit
35.2.3. 0.1 n-
resistor
-
Switch off
the
instrument
-
Set range
switch to
position
100 mfl
-
Make a
measuring set-up
with a
standard
resistor
of 100 mft
as
shown in
fig. 18
—
Check that the
voltage
drop across
resistor 71 1 is
the
same as that
across the
standard
resistor of 1 00
mft.
Tolerance: <
0.3 %.
—
Adjustment is
possible by
using solder
tin
between the
resistance wire
and the
normal wire
Fig.
18.
Measuring set-up
with
standard
resistor
of 100 mD.