11
7. Common Failure Analysis and Troubleshooting
Failure phenomenon
Failure cause
Solution
Power on, the front panel
display screen and power
indicator are both off.
Switching power supply couldn't
start; equipment; internal DC
power supply is not working.
Check if the power supply is normal
(should be AC: 110V-250V). If the
supply voltage is normal, it could be a
failure of switching power supply
module. Please contact the dealer or
our company.
Power on; the display screen is
off, only the power indicator is
on.
The internal microprocessor is not
working.
Please contact the dealer or our
company.
Power on; the optical output
power displayed on the front
panel display screen and laser
status indicator are both normal,
but the actual measured optical
output power is low.
1. The poor quality of the test
jumper.
2. The active fiber connector or
adapter may be contaminated.
3. The ceramic tube in the
adapter may have been
broken.
1. Replace with good quality test
jumper.
2. Clean the contaminated active fiber
connector or adapter. Specific
operation methods see “The clean
and maintenance method of optical
fiber connector”.
3. Replace the damaged adapter.
After initial startup, the image of
the optical contact point has
obvious netlike curve or large
particles highlights.
1. The received optical power of
the optical contact point is too
high; the output level of the
optical receiver module is too
high and intermodulation
index of RF signal
deteriorates.
2. The RF signal input of the
optical transmitter is too high;
beyond the device AGC
control range, results in
deterioration of the
intermodulation index.
3. The intermodulation index of
RF signal input of the optical
transmitter itself is poor.
1. Check the received optical power
of the optical contact point and
make appropriate adjustments.
2. Check the input level of the optical
transmitter RF signal, and adjust to
the device required input range.
(RF signal input level should be
72--88dBμV).
3. Check the intermodulation index of
the RF signal input of the optical
transmitter and make appropriate
adjustments.
After initial startup, the image of
the optical contact point has
obvious noises.
1. The received optical power of
the optical contact point is not
high enough, results in
decrease of C/N.
2. The RF signal level input of
the optical transmitter is too
low; make modulation degree
1. Recover received optical power of
the optical contact point by
cleaning the active fiber connector
or. Specific operation methods see
“Clean and maintenance methods
of optical fiber connector”.
2. Check the RF signal level input of
Optical Transmitter
User Manual
L-RF-4mW-TX
www.questtel.com
