Maintenance
6
Keysight U1401B User’s and Service Guide
137
Table 6-2
Troubleshooting
Malfunction
Identification of the problem
No LCD display after switching ON – Check the position of the slide switch. Set it to the M or M/S position
– Check the batteries. Recharge or replace the batteries if necessary
No beeper tone
Check the setup mode to see if the beeper has been disabled (“OFF”). Select the desired
driving frequency
Failed to measure current
Check fuse 1
No output signal when:
– the
annunciator is
displayed.
– the
OUTPUT
key is pressed and
the
annunciator only
appeared for a short while
before being replaced by the
annunciator.
– The batteries are low
– Check the position of the slide switch. Set it to the M/S position
– Check the external load to see whether the rated limit is exceeded.
– Check whether the loop has a 24 V power. If yes, use the special yellow test lead for mA
simulation (see
Chapter 5, “Simulation Mode for mA Output”
)
– Check fuse 2
No charging indication
– Set the slide switch to the CHARGE position
– Check the external adapter to see whether the output is 24 VDC and whether it is
properly plugged in to the charging terminal
– Check the line power voltage (100 VAC to 250 VAC 47 Hz/63 Hz) and the power cord
Remote control failure
– Make sure that the optical side of cable is connected to the instrument and the text side
of the connector cover should be facing up
– Check the baud rate, parity, data bit, and stop bit (default settings: 9600, n, 8, 1)
– Install the driver for IR-USB on your PC
