Front Panel Tests; Zero Output - Fluke 5220A Instruction Manual

4-22. Front Panel Tests

Use the following procedure to check the operation of the 5220A front-panel controls and
LEDs:
1. With the unit in the standby mode, connect jumper wires between the enabled
(front/rear) output terminals. Use a 4-inch length of 16-gauge insulated wire.
2. Press the OPR/STDBY pushbutton. The OPR LED should light and the STDBY LED
should go out.
3. Press the INPUT pushbutton to select the rear input.
4. Return input control to the front panel by pressing the INPUT pushbutton. The
FRONT LED should light and the REAR LED should go out.
5. Remove the jumper wire from the output terminals. The unit should switch to the
standby mode and the OVERCOMPLIANCE LED should light.
6. Reinstall the jumper wire at the output terminals.
7. Clear the overcompliance condition by pressing the OPR/STDBY switch. Set the unit
to the operate mode.
The THERMAL CUTOFF LED will light only when the output
stage of the 5220A is overheated. This is a failure mode that
should not be invoked for test purposes. The LOCAL
pushbutton and the REMOTE, LOCAL LOCK OUT LEDs are
remote control features that require remote commands for
operation.

4-23. Zero Output

The following procedure checks the zero output of the 5220A in both the standby and
operate modes:
1. Connect the load resistor (0.1 ohm) to the enabled (front/rear) output terminals.
2. Connect the DVM to the sense terminals on the load resistor and select the 100 mV
dc range.
3. With the 5220A in the standby mode, read the voltage drop across the load resistor.
The reading should be 0 +/-5 V dc.
4. Connect a short jumper wire between the front VOLTAGE INPUT terminals.
5. Set the 5220A to the operate mode. The OPERATE LED should be on and the
STANDBY LED off.
6. Read the output voltage on the DVM. It should be 0 +/-100 V dc.
7. Set the 5220A to standby and remove the jumper wire from the VOLTAGE INPUT
terminals.
8. Disconnect the load resistor from the output terminals on the 5220A.
Caution
Maintenance
4
Performance Test
4-9