Troubleshooting
15
9.1 Power and Indicators
Problem
Remedy
No Power
Confirm that the switch is in the “ON” position, and that the lamp is illuminated.
Confirm that power connections are secured at the amplifier and at the
receptacle. Make sure the receptacle is active, outputting the proper mains
voltage.
If there is still no power, check the fuse. Remove power cord from the AC outlet
and from the machine and then, using a flat head screwdriver, remove the fuse
holder located directly below the power connector. Confirm that the fuse is
good by looking at the wire connected to the ends of the fuse. If the wire is
broken, replace the fuse with another, with the same value.
9.2 Video Signal
Problem
Remedy
No video at the output
device, regardless of
input selected.
Confirm that your sources and output device are powered on and connected
properly. Video signals connected to the input of your switcher should be of an
identical signal format at the output of your source. Video signals at the output
of your switcher should be of an identical signal format as at the input of your
display or recorder.
Confirm that any other switchers in the signal path have the proper input and/or
output selected.
Video level is too high
or too dim.
Verify that the video line is well interfaced through 75ohm impedance,
otherwise it results in a video level that is too high or too dim when looping is
performed and the termination switches are not in proper position.
Confirm that the 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.
Weak switcher input
signals
The switcher contains two internal trimmers, accessed via two holes in the
base of the switcher. These allow, if necessary, to adjust switcher output signal
level. For example, if you are using a long cable with heavy losses, you can
compensate for it by fine-tuning the signal using the two trimmers. One trimmer
adjusts the gain of the whole video signal and the other adjusts only the high
frequencies of the video which have been degraded by a low quality cable. The
hole closer to the power socket controls the cable compensation the other
controls the video level.
WARNING!
Do not use the trimmers except in cases where the cable losses
result in poor resolution of detail or when the whole signal level crashes.
Once they have been touched, the accurate signal transparencies that have
been fine-tuned in the factory are lost. To readjust to the original signal status
you need a stable signal generator and a good quality signal analyzer.
Noise bars are
“rolling” 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:
Confirm that all interconnected equipment is connected to the same phase of
power, if possible.
Remove equipment connected to that phase that may introduce noise, such
as motors, generators, etc.
Disconnect all interconnect cables and reconnect them one at a time until
ground loop reappears. Disconnect the affected cable and replace, or insert
an isolation transformer in the signal path.
