Philips PM32671 Service Manual page 90

5.5.6. Triggering
5.5.6.1. Trigger symmetry
-
Set controls
the as
Set S15 to 50p.
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- Set to 2 V .
- Apply a sine-wave signal 1.6V p-p frequency 10kHz to input A.
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Adjust the generator to
- Push the SLOPE switch S8 for positive triggering.
- Set R6 fully clockwise.
- Note the starting-point
- Pull the SLOPE switch S8 for negative triggering.
- Set R6 fully counter-clockwise.
- Note the starting-point of the trace.
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Check that in both situations described above, the distances between the trigger points and the top respec-
tively the bottom of the sine-wave signal are equal; if necessary readjust R1054 (fig. 5.2.) for an optimal
result.
- Remove the input signal.
5.5.6.2. Trigger sensitivity
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Set the controls as indicated in fig. 4.1.
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Set S9 and S11 to .2V.
- Apply a sine-wave signal 80mV. frequency 10kHz to the input A.
- Pull and push the SLOPE switch S8.
Check that the trace is well triggered; if necessary readjust R388 (fig. 5.1
-
5.5.6.3. Trigger balance channel
- Depress TRIG VIEW of
- Depress AUTO PP and TRIG of S3.
- Depress 0 of S17 and S18.
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Depress LF of S20 and A of S23.
- Set the trace in the vertical centre of the screen by means of the LEVEL control R6.
- Depress DC of
- Check that the trace is in the vertical centre of the screen; if necessary readjust
- Depress B of S23.
- Check that the trace is in the vertical centre of t h e screen; if necessary readjust
- Depress EXT of S23.
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Check that the trace is in the vertical centre of the screen; if necessary readjust R1103 (see fig. 5.2.).
5.5.6.4. Composite balance
- Depress A of S1.
- Depress A of S23.
- Depress AUTO (AUTO PP and TRIG) of
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Put AMPLIDIV in position 0.2V.
- Release all the pushbuttons of
-
Depress DC of S17.
- Apply a sine-wave signal, frequency 10kHz to input X2 (A).
- Set the trace-height to 4 div.
- Set S15 to
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Depress A and B (COMP) of S23.
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Adjust R964 (fig. 5.2.) so that the starting point of the trace does not shift when switching to position
DC of S20.
indicated in fig. 4.1.
trace height of 8 div.
a
of
the trace.
A,
B and E X T
S3.
.).
R959 (see fig. 5.2.).
R962 (see fig. 5.2.).
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