Vertical Deflection; Low-Frequency Response - Fluke Autoranging CombiScope PM3370B Service Manual

6 - 10
7 -
Press the ACQUIRE menu key.
8 - Select BW LIMIT 'on' via the VERT MENU key.
9 - Slowly increase the frequency to 20 MHz and verify that the vertical deflection has decreased
to 4.2 div approximately at 20 MHz.
10 - Switch the bandwidth limiter to 'off'.
Requirements:
- The vertical deflection must be 4.2 divisions or more. For the bandwidth limiter the requirement is
4.2 div approximately at 20 MHz.
Repeat the above settings and procedure for CH2, CH3 and CH4. PM3370B/80B/90B: check CH2
and TRIG VIEW via EXT TRIG input. Oscilloscope in 1V/div and generator voltage 5 Vpp into 50Ω.
Termination resistor directly at generator output. Use a BNC / probe tip adapter between termination
and 10:1 probe. Adjust the amplitude at 50 kHz to 5 divisions. Check that the amplitude at higher
frequencies does not drop below 3.5 div.
- Press the ANALOG key ('DIGITAL MODE' is displayed briefly) and repeat the tests in this
section for the digital mode. Adjust the MAIN TB TIME/DIV if required.

6.3.11 Vertical deflection; low-frequency response

This test verifies the lower transition point of the vertical bandwidth.
Test equipment:
Fluke 5500A mode: wavegen, wave sine (Alternative: function generator PM5136).
Test set up:
Settings/procedure:
1 - Apply a 5 kHz sine wave signal of 600 mV (pp into 50Ω) to input CH1, and press the AUTOSET
key.
2 - Set CH1 to 0.1V/div.
3 - Adjust the input signal to an amplitude of exactly 6 divisions.
4 - Lower the frequency to 10 Hz and verify that the displayed amplitude does not drop below 4.2
divisions.
Requirements:
- The vertical deflection must be 4.2 divisions or more.
Repeat the above settings and procedure for CH2, CH3, and CH4. PM3370B/80B/90B: check CH2
and TRIG VIEW via EXT TRIG input.
Press the ANALOG key ('ANALOG MODE' is displayed briefly) to return to analog mode.
PERFORMANCE TEST