Philips PM6302 Instruction Manual page 37

37
3.5.2. Adjusting procedures
3.6.2.1. 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 (R713/10)
Measuring fault < 1% (e.g. with PHILIPS PM 2421 digital multimeter}
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 f, solder resistor 658 into the circuit and replace resistor 635 by a resistance decade also adjusted
to the value found. i
— By alternating the adjustment of scale points 1 and 10 in range x1 kQ, the definitive values
for resistors 635
and 637 can be determined.
Scale point 1 must be adjusted with a sample of 1 kQ+ 1 %e , while scale point 10 must be adjusted
with a
L
10kQ+ 1 %e sample.
3.5.2.2, Reference capacitor
— From table | take the value for Ry 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 x10 nF
— Set frequency scale to 10
— Connect a sample of 100 nF + 1 %e between sackets I-E
;
— Reduce the detuning of the bridge to a minimum by varying capacitance 517
— Solder the selected capacitor value into the circuit
3.6.2.3. 0.1 Q- resistor :
— Switch off the instrument
— Set range switch to position 100 m2
!
— Make a measuring set-up with a standard resistor of 100 m2 as shown in fig.
18
i
i
— Check that the voltage drop across resistor 711 is the same as that across the standard resistor of 100 mi,
'
!
Tolerance: < 0.3 %.
— Adjustment is possible by using solder tin between the resistance wire and the normal wire
errore 1%
leg. Philips
PM 2621
©
eg Phitips
PE 1510
WAGED
Fig. 18. Measuring set-up with standard resistor of 100 mQ.