True-rms Digital Multimeters
Performance Tests
15
Factory Default
Prior to completing the Performance tests Reset the Meter to the factory defaults as
follows:
1. Power the Meter on in any function.
2. Press F4 (Setup) and select Reset using arrow keys.
3. Press F3 (Meter).
4. Press F1 (OK). The Meter should go through power up routine.
Power LED Test
The Meter’s power button has an LED backlight. To test the LED, power on the meter,
verify that the power button lights for approximately 4 seconds, and then extinguishes.
Backlight Test
To test the backlight, press the
T button twice. Note that the backlight comes on at two
different intensity levels.
Current Terminal Sensing Test
This test determines whether or not the Input Alert™ is functioning properly.
Note
Before conducting this test, make sure the beeper is not disabled in setup.
1. Turn the Meter on.
2. Install a test lead in the mA/μA input terminal.
3. Turn the rotary switch to all functions, except current functions. Note that the beeper
Chirps continuously and the LCD displays a warning.
4. Turn the rotary switch to the A/mA position. Note that the beeper does not chirp and
the leads warning is not displayed.
5. Remove the test lead and install it into the A terminal. Repeat steps 3 and 4.
Keypad Test
Note
Before conducting this test, make sure the beeper is not disabled in setup
mode.
To test that the keypad buttons are active Turn the Meter on and push each button
separately. Each button push should cause the Meter to beep.
LCD Test
The 28X uses a dot matrix LCD. To best test the LCD pixels, use the following
procedure.
1. Turn the rotary switch knob to k and turn the Meter on.
2. Push F4 for Setup and select contrast.
3. Push the Backlight button twice for max brightness and use the F1 and F2 softkeys to
adjust Contrast for the brightest display.
4. Push the “i Info” button and scroll the text with F1 and F2. Inspect the LCD display
for missing pixels or areas of the display that may be unreadable due to pixel defects.
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