Philips PM32671 Service Manual page 89

5-1 8
5.5.5.7. Chopper cross-talk from channel A to B
- Set the controls as indicated in fig. 4.1.
-
Depress CHOP pushbutton of S1.
-
Set the AMPL/DIV switches S9 and S11 to 20mV.
-
Apply to X2 (A) a square-wave signal of 120mV, frequency 10kHz and with a rise-time
- Put the TIME/DIV switch S15 to O.lms.
- Check that the cross-talk from channel A to B does not exceed 1.5% (0.1 div.).
5.5.5.8. Bandwidth check channel A (B)
-
Depress the X MAGN switch S7
- Set the MTB TIME/DIV switch S15 to 5 p .
- Apply a sine-wave signal, freq. 50kHz, constant amplitude of 12mV to input A (B).
-
Depress A (B) of S1.
-
Depress A (B) of S23.
- Set the AMPL/DIV switch
- Check that the trace height is exactly 6 div.
- Increase the frequency of the input signal from 50kHz to 80MHz (constant amplitude 12mV).
-
Check that the trace height i s
- Set the AMPL/DIV switch S9 (S11) to 20mV.
-
Apply a sine-wave signal, freq. 50kHz, constant amplitude of 120mV to input A
- Check that the trace height i s exactly 6 div.
-
Increase the frequency of the input signal from 5OkHz to 100MHz (constant amplitude 120mV).
- Check that the trace height
- If the specifications mentioned above are not met, readjust the instrument according to chapter 5.5.5.3.
and 5.5.5.4.
-
Set the AMPL/DIV switch
-
Apply a square-wave signal, frequency 50kHz, constant amplitude of 12mV to input A (6).
- Depress A (B) of S23.
- DepressTRIGVIEWofSI.
-
Set the trace in the vertical centre of the screen by means of the LEVEL control R6.
- Check that the trace height is exactly 6 div.
-
Increase the frequency of the input signal from 50kHz to 6OMHz (constant amplitude 12mV).
- Check that the trace height i s
- Depress EXT of S29.
- Apply a sine-wave signal, freq. 5OkHz, constant amplitude 0.8V to input EXT (X5).
- Check that the trace height is exactly 4 div.
- Increase with frequency of the input signal to 70MHz (constant amplitude 0.8V).
- Check that the trace height is
- Remove the input signal.
- If the specification mentioned above i s not met readjust the instrument according to chapter 5.5.5.6.
4.2 div. over the whole freq. range.
is 2 4.2 div. over the whole freq. range.
4.2 div.
2.8 div.
1 ns.