KRAMER ELECTRONICS LTD
9
11 TROUBLESHOOTING
1. Please note that if the output signal is disturbed or interrupted by
very strong external electromagnetic interference, it should
return and stabilize when such interference ends. If not, turn the
acceptor/source power switch off and on again to reset the
machine.
2. If the following recommended actions still do not result in
satisfactory operation, please consult your KRAMER Dealer.
11.1 Video and other High Frequency Signals
Problem
Remedy
No signal at the output
device, regardless of
input selected.
1. Confirm that your sources and output device are powered on and connected
properly.
2. Confirm that any other devices in the signal path have the proper input and/or
output selected.
3. Confirm that the distance used in your system is not larger than the
recommended distance for this optic fiber system.
4. Use a Video Tester to test the video path leading to/from your transmitter
/receiver (see section 4.1 " Video Tester")
Signal level is too high
or too dim.
1. Verify that the video signal is well matched through 75ohm impedance;
otherwise it results in a signal level that is too high or too dim.
2. Confirm that you are using the right optic fiber cable suitable for the system, and
that you are within the recommended operating range.
3. Confirm that there are no sharp bends or breaks along the optic fiber. Sharp
bends or loops deteriorate the signal due to energy loss resulting from reflections
and exceeding of the critical angle of transmission. Adjust levels if needed, as
described in sections 7.1.1 and 7.1.2.
4. Confirm that the video connecting cables are of high quality, properly built and
terminated with 75ohm BNC connectors. Check level controls located on your
source input device or output display or recorder.
Problem
Remedy
Noise bars "roll" up or
down in the output
image
or:
Low Frequency Hum in
the output signal
The fiber optic system is free from induced hum and ground currents, as it provides a
pure galvanic isolation, however, this problem may appear in your system due to
other components used. Hum bars (ground loop) are caused by a difference in the
ground potential of any two or more devices connected to your signal path. This
difference is compensated by passing that voltage difference through any available
interconnection, including your video cables.
WARNING! DO NOT DISCONNECT THE GROUND FROM ANY PIECE OF
VIDEO EQUIPMENT IN YOUR SIGNAL PATH!
Check the following to remove hum bars:
1. Confirm that all interconnected video equipment is connected to the same phase
of power, if possible.
2. Remove equipment connected to that phase that may introduce noise, such as
motors, generators, etc.
3. Disconnect all interconnect cables and reconnect them one at a time until ground
loop reappears.
4. Disconnect the affected cable and replace, or insert an isolation transformer in
the signal path.
