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KRAMER Electronics, Ltd.
12
Problem Remedy
Noise bars “roll” up or
down in the output
image
or:
Low frequency hum in
the output signal
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 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
the ground loop reappears. Disconnect the affected cable and replace, or
insert an isolation transformer in the signal path.
16.3
Audio Signal
Problem Remedy
No audio at the output
device, regardless of input
selected
1. Confirm that your sources and output device are turned on and
connected properly. Audio signals connected to the input of your
switcher should be properly wired to the output of your source. Audio
signals connected to output of your switcher should be properly wired
to the input of your switcher or recorder.
2. Confirm that any other switchers in the signal path have the proper
input and/or output selected.
Audio level is too low 1. Confirm that the connecting cables are of high quality and properly
built. Take special care in noting the wiring configuration of balanced
to unbalanced cables.
2. Check level controls located on your source input device or output
display or recorder.
16.4
Control
Problem Remedy
No control of switcher
from PC software
1. Confirm the wiring of the connecting cable. Cable length should not
exceed 25 feet.
2. Confirm that all DIP switches on the switcher have been set properly.
Keep in mind that if you are only controlling one switcher on a
specific port, that switcher must be assigned as unit “1”.
3. Confirm that the baud rate of your computer COM port is set to the
same as that of your switcher (9600-Baud). Confirm that the proper
COM port is selected in the control software.
4. Confirm that bi-directional communication is enabled on all
switchers. With custom software, do not send multiple commands at
the same time. The switcher must complete one command and send a
reply before receiving another.
5. Make sure that all switchers are powered up. Communication between
the machines can only be done when all machine are turned on.