GMC TopKick 2007 Owner's Manual page 189

Radio Messages
CAL (Calibration): The audio system has been
calibrated for your vehicle from the factory. If
CAL appears on the display it means that the radio
has not been configured properly for your vehicle
and must be returned to your dealer for service.
LOC (Locked): This message is displayed when
®
the THEFTLOCK system has locked up. Take
the vehicle to your dealer for service.
If any error occurs repeatedly or if an error cannot
be corrected, contact your dealer.
Playing a Cassette Tape
The tape player is built to work best with tapes
that are up to 30 to 45 minutes long on each side.
Tapes longer than that are so thin they may not
work well in this player. The longer side with
the tape visible should face to the right. If you hear
nothing or hear a garbled sound, the tape may
not be in squarely. Press the eject button to
remove the tape and start over.
If the ignition and the radio are off, press the eject
button or the RCL knob to insert and to begin
play of a tape. If the ignition is on and the radio is
off, the tape can be inserted and begins playing.
CAS (cassette) appears on the display when
a tape is inserted.
While the tape is playing, use the VOL, AUDIO,
and SEEK controls just as you do for the
radio. The radio displays UP if the top side of the
tape is playing. DN (Down) appears if the
bottom side is playing. The tape player plays the
other side of the tape when it reaches the end.
Cassette tape adapter kits for portable CD players
works in the cassette tape player. See "CD
Adapter Kits" later for more information.
The tape bias is set automatically when a metal or
chrome tape is inserted.
If an error appears on the display, see "Cassette
Tape Messages" later in this section.
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