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Troubleshooting
JBL
Problem
Possible Cause and Solution
Hum
Interference with Radio or TV
Erratic recall of modes
If all else fails...
Finding and eliminating audio hum in a complex installation can be a
very frustrating task. Often, the easiest way to identify the culprit(s) is
to systematically eliminate devices from the audio chain. If Cable TV is
connected to any component in the system, start by unplugging the
Cable completely, preferably right at the wall jack. If this eliminates, or
greatly reduces the hum, it is worth a call to your Cable company. A
quick fix, assuming your cable is round 75Q. wire, is to attach a 75-300Q
transformer to the end, then attach a 300-75Q transformer to that, so
that the end is back to a round 75Q wire. There are commercially
available antenna lead isolators which may provide additional insula-
tion from electrical surges.
If you are using a video projector, disconnect the video out from the
SDP-2 to the projection system to see if the video equipment is causing
the problem.
The SDP-2 does generate minimal amounts of RF energy and is in
compliance with FCC rules and CE standards. If some interfering noise
is noted, move AM loop and FM "T" type antennas away from the
SDP-2-and reorient them as necessary. Use shielded cable for FM and.
TV antenna feeds.
Severe power surges or sagscan confuse the SDP-2 memory. To correct,
or if you simply want to start over, restore the factory defaults with the
procedure described at the end of this section.
Turn off all amplifiers. Turn the master power switch on the SDP-2rear
panel OFF, wait 10 seconds, then turn it ON again. This causes the unit
to run a diagnostic self-test routine which takes a couple of seconds. If
the SDP-2 LCD displays normally at the end of this test, no problems
have been found with the SDP-2 circuitry. If the internal tests fail, the
LCD may display anerror message, or no message atall. If this happens,
contact JBL.
If you find that your custom settings are routinely being corrupted, the
lithium battery in the SDP-2 may be faulty. This part is not field-
replaceable — contact JBL.
If the unit is still behaving erratically, perform the Restore Defaults
procedure described on the following page.
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