50
Lexicon
Troubleshooting
Problem
Possible Cause and Solution
Hum
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 75
Ω
wire, is to attach a 75-300
Ω
transformer to the end, then attach a 300-75
Ω
transformer to that, so
that the end is back to a round 75
Ω
wire. There are commercially-
available antenna lead isolators which may provide additional
insulation from electrical surges.
Clicking in audio
In some systems a very slight clicking may be audible with sources that
are at a consistently low level. This is an artifact of the CP-3
PLUS
's
S/N Optimization system. To prevent this, the S/N Optimizer for each
input this is observed on should be turned OFF, although defeating it
will result in an increase in background noise. As always, be sure to set
the input level as high as possible.
Interference with AM, FM,TV
The CP-3
PLUS
does generate minimal amounts of RF energy and is in
or Cable TV
compliance with FCC rules. If some interfering noise is noted, move
AM loop and FM "T" type antennas away from the CP-3
PLUS
and reorient
them as necessary. Use shielded cable for FM and TV antenna feeds.
Erratic recall of modes
Severe power surges or sags can confuse the CP-3
PLUS
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.
Rear speaker off in THX mode
See note on side speakers, page 21.
If all else fails…
Turn off all amplifiers. Turn the master power switch on the CP-3
PLUS
rear 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 CP-3
PLUS
LCD displays normally at the end of this test,
no problems have been found with the CP-3
PLUS
circuitry. If the internal
tests fail, the LCD may display an error message, or no message at all.
If this happens, contact Lexicon.
If you find that when the rear-panel master POWER switch is turned
ON, the CP-3
PLUS
routinely displays the message "INITIALIZING", or if
you find that User settings are being replaced with factory defaults after
power OFF, the lithium battery in the CP-3
PLUS
may be faulty. This part
is not field-replaceable, contact Lexicon.
If the unit is still behaving erratically, perform the Restore Defaults
procedure described on the following page.
