MultiDyne CTV-2000-FTX Series - Manual (Page 12)

CTV2000-FTX Series CATV Fiber Optic Transmitter Users’ Manual
12
Chapter 9 Troubleshooting
SYMPTOM FAULT ACTION
No VFD or LED display
after turning on the power
No input power or a problem with
the internal switching power
supply.
Check input AC voltage to the power
supply (AC90V~250V), if the voltage
is normal, usually the cause is the
internal switching power supply,
contact MULTIDYNE.
After turning on power,
VFD monitor and LED
normal, but optical output
power low.
1. Check jumper quality
2. Contaminated optical active
connector or adapter
3. Damaged ceramic ferrule in
adapter
1. Swap to a good test jumper
2. Clean contaminated fiber active
connector or adapter
3. Swap the damaged adapter
After connecting to
network, all TV channels
have obvious noise point.
1. Low received optical power,
causing poor C/N.
2. RF input level too low for
sufficient laser modulation.
3. System link path C/N too low.
4. Back-reflection from bad or
dirty optical connectors
1. Clean fiber active connector or
adapter (Chapter 7 Cleaning and
maintenance).
2. Check RF input levels to
transmitter. (15-25dBmV)
3. Check link loss.
4. Use only angled (SC/APC) optical
connectors or fusion splice where
necessary.
After connecting to
network, only some TV
channels have a degraded
SNR.
Some channels SNR too low.
Check the individual channel signal
C/N or SNR.
Check the flatness of the RF input
signal
After connecting to
network, some TV
channels have obvious
ripple, beats, lines, or
distortions. 1. Optical input power to
receiver too high.
2. RF modulation too high.
3. RF input drive to transmitter
too high.
1. Check input power at optical
receiver and pad if necessary.
2. Check optical transmitter
modulation level parameter, and
readjust if too high
3. Make sure the RF input level is
within the range (15~25dBmV)
Addendum note: to reset the transmitter to the default settings, as shipped from the factory, follow the following
steps:
1) Power unit OFF.
2) While holding in both the UP and DOWN buttons, power the unit ON.
3) The VFD will display “Test Mode”, and the transmitter will emit a loud beeping noise.
4) Power the unit OFF for 5 seconds, and then back ON. The modulation and display settings have now been
restored to the factory defaults. These settings will work for 99% of the applications, and it is rarely needed
to deviate from these. Please consult the factory if unsure.