Philips PM 5125 Manual page 30

34
E. SINE WAVE VOLTAGE
1. —Set switch SK3 to position X 102.
— Set [he frequency dial to position 10.
— Set switch SK2 to position
— Turn trimmer R42 and R45 fully anti-clockwise (R=0).
— Adjust trimmer R40 so that the voltage between test-points 10 and
11 of the oscillator board is 16 mV ± 10%.
— Measure the voltage between terminals BU4 and BU7 by means
of a diode voltmeter and note the value.
2. —Adjust trimmer R40 so that the voltage between test-points 10
and 11 of the oscillator board is 20 mV ± 10%.
— Measure the voltage between terminals BU4 and BU7; [his value
must be smaller than the value noted in point 1.
3. —Turn trimmer R42 a little clockwise.
— Adjust trimmer R40 according to point 1 and note the output
voltage.
— Adjust trimmer R40 according to point 2 and compare this output
voltage with the value noted.
4. —Repeat the adjustments until both values are equal. Tolerance: 1%.
— Adjust trimmer R40 according to point 2.
5. —Set switch SK3 to position x 102.
— Set the frequency dial to position 50.
— Set attenuator R2 fully clockwise.
— Adjust trimmer R52 so that the voltage between terminals BU4 and
BU7 is 10.3 Vrms ± 0.1 Vrma. This voltage should also be present at
terminals BUl—BU2.
6. —Set switch SK3 to position x 102, set the frequency dial to position
50 and turn continuous attenuator R2 until the voltage between
terminals BU4 and BU7 is 10 Vrms (reference value).
— Set switch SK3 and the frequency dial successively to the positions
indicated in the table below and check that the corresponding
voltage between BU4 and BU7 is within the indicated limits.