Fluke 5220A User Manual
Maintenance
Replacement of Selected Components
4
4-15
8.
Set the 5220A to the standby mode.
9.
Disconnect the shunt and voltmeter from the 5220A output terminals.
4-36. Overcurrent Adjustment
This procedure is used to adjust the overcurrent trip level of the 5220A. The overcurrent
adjustment (R21) is located on the A8 Analog Control PCB Assembly.
adjustment (R21) is located on the A8 Analog Control PCB Assembly.
1.
Connect the load resistor (0.1 ohm) to the enabled output terminals on the 5220A.
2.
Set the calibrator output to 23.5 V rms, 50 Hz.
3.
Set the 5220A to the operate mode. If the unit switches back to standby, turn R21 (on
the A8 Analog Control PCB Assembly) counterclockwise until the operate mode can
be enabled.
the A8 Analog Control PCB Assembly) counterclockwise until the operate mode can
be enabled.
4.
Adjust R21 clockwise until the 5220A switches to the standby mode. Both the
STDBY and OVERCURRENT LEDs should light.
STDBY and OVERCURRENT LEDs should light.
5.
Disconnect the 0.1 ohm load resistor from the 5220A output terminals.
4-37. Overvoltage Adjustment
This procedure is used to adjust the overvoltage trip level for the 5220A. The overvoltage
adjustment (R9) is located on the A8 Analog Control PCB Assembly.
adjustment (R9) is located on the A8 Analog Control PCB Assembly.
1.
Connect the 1 ohm load resistor to the enabled output terminals on the 5220A.
2.
Set the ac voltage calibrator output for 3.3 V rms, 50 Hz.
3.
Set the 5220A to the operate mode. If the unit switches back to standby, turn R9 (on
the A8 Analog Control PCB Assembly) counterclockwise until the operate mode can
be enabled.
the A8 Analog Control PCB Assembly) counterclockwise until the operate mode can
be enabled.
4.
Adjust R9 clockwise until the 5220A switches to the standby mode. Both the STDBY
and OVERCOMPLIANCE LEDs should light.
and OVERCOMPLIANCE LEDs should light.
5.
Disconnect the load resistor and the ac voltage calibrator from the 5220A.
6.
Set the 5220A POWER switch to OFF.
7.
Disconnect the unit from line power.
8.
Install the inner cover and top cover on the 5220A.
4-38. Replacement of Selected Components
The A5 Preamplifier PCB Assembly contains a series of three selected parts that may
have to be changed after repairs have been made on the PCB. All three selected parts are
resistors. Two (R11, R12) are associated with the Input Offset Adjustment (R6); the third
(R13) affects the DC Accuracy Adjustment (R3). Resistors R11 and R12 are selected to
place R6 at approximately midrange when it is properly adjusted. Resistor R13 is selected
to accomplish the same thing for R3. When the travel of either R3 or R6 limits proper
adjustment, the associated selected resistor(s) should be replaced. Follow the appropriate
procedure for parts selection.
have to be changed after repairs have been made on the PCB. All three selected parts are
resistors. Two (R11, R12) are associated with the Input Offset Adjustment (R6); the third
(R13) affects the DC Accuracy Adjustment (R3). Resistors R11 and R12 are selected to
place R6 at approximately midrange when it is properly adjusted. Resistor R13 is selected
to accomplish the same thing for R3. When the travel of either R3 or R6 limits proper
adjustment, the associated selected resistor(s) should be replaced. Follow the appropriate
procedure for parts selection.