Fluke PM3082 Service Manual page 440

6 - 1 4
5 - Set CH1 and CH2 to DC input coupling.
6 - Press the CH1+CH2 key; to activate the added mode.
7 - Press the INV key of CH2; the result is the display of the differential signal of CH1-CH2.
8 - Press the ON keys of CH1 and CH2; this switches CH1 and CH2 off and only the differential
signal of CH1 CH2 display is now visible.
9 - Readjust the VAR function of CH1 or CH2 for minimum amplitude.
Requirements:
Verify that the amplitude of the CH1-CH2 differential signal is less than 0.32 divisions.
Repeat the above settings and procedure for CH3 and CH4(PM3084/94 only).
6.3.18 Vertical deflection; LF linearity
The linearity of the vertical amplifier is checked by moving a signal with a fixed amplitude vertically
over the entire screen area.
Test equipment
Fluke 5500A mode: wavegen, wave square (Alternative: function generator PM5136)
Test set up:
5500A
Settings/procedure
1 - Apply a 50 kHz square-wave signal of 200 mV (pp) to input CH1.
2 - Press the AUTOSET key and set CH1 to 0.1 V/div.
3 - Move the square-wave signal to the vertical center of the screen.
4 - Adjust the generator output so that the displayed amplitude is exactly 2 divisions.
5 - Use the CH1 POS control to shift the signal across the central 6 divisions of the screen.
Requirements
Verify that the amplitude in the two upper and lower divisions is between 1.96 ...2.04 divisions
(+/-2%).
Repeat the above settings and procedure for CH2, CH3 and CH4.
OSCILLOSCOPE UNDER TEST
5 0 0 CABLE
PERFORMANCE TEST