Vertical Deflection; Base Line Instability - Fluke Autoranging CombiScope PM3370B Service Manual

PERFORMANCE TEST

6.3.20 Vertical deflection; base line instability

In the following test, several adjustments of balance, offset and jump, are checked.
Test equipment
None
Settings/procedure and requirements:
1 - Press the AUTOSET key (no input signal) and set CH1 to 5V/div.
2 - Use the CH1 POS control to position the trace in the vertical middle of the screen.
3 - Press both CH1 AMPL keys simultaneously to select the VARiable mode. The readout
changes to 5.00V. The input sensitivity can be adjusted now in very fine steps between 2 mV
and 12.5V/div.
4 - Press the 'V' key and verify that the base line jump is not more than 0.2 divisions between
5.00V to 12.5V/div.
5 - Press the 'mV' key and verify that the base line jump is not more than 0.2 divisions between
12.5V/div to 5 mV/div.
6 - Press the ON keys of CH2 and CH1; CH2 is now on and CH1 is off.
7 - Using the CH2 POS control, position the trace in the vertical middle of the screen.
8 - Press both CH2 AMPL keys simultaneously to select the VARiable mode. The readout
changes to 5.00V. The input sensitivity can be adjusted now in very fine steps between 2 mV
and 12.5V/div.
9 - Press the 'V' key and verify that the base line jump is not more than 0.2 divisions between
5.00V to 12.5V/div.
10 - Press the 'mV' key and verify that the base line jump does not 0.2 divisions between 12.5V/div
to 5 mV/div.
11 - Press the INV key repeatedly and verify that the base line jump is not more than 0.2 divisions.
For the PM3394B and PM3384B repeat the above procedure for CH3 and CH4. The CH3 settings
are equal to those of CH1; the CH4 settings are equal to CH2.
For PM3390B, PM3380B and PM3370B no further steps required.
6.3.21 Delay difference between vertical channels
The delay difference between CH1, CH2, CH3, and CH4 is checked here.
Test equipment:
Fluke 5500A mode: edge (Alternative: Square wave calibration generator PG 506).
Power splitter
Test set up:
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