Radio – circuit operation rev: 09/2001

RADIO – CIRCUIT OPERATION REV: 09/2001

CIRCUIT OPERATION

Battery Voltage is provided to the radio at all times through the P wire. In addition to the anti-theft feature, this input voltage keeps the preset station memory alive. Whenever battery power to the unit is lost, the anti-theft code must be entered and the preset stations must be reprogrammed (if enabled). When the Radio (Z111) and the igntion are turned on, the voltage signal through the WK wire to the control head ‘wakes up’ the unit. The Radio (Z111) plays, the LCD display comes on and the control buttons illuminate. On some models, when the park lamps or headlamps are turned on, a voltage signal is sent through the RW wire to dim the LCD display and control buttons for night driving. Radio (Z111) signals are received via a coaxial cable from the side screens and antenna amplifiers. The amplifiers filter and boost the signal from the side screen, using power supplied on WO wires, whenever the ignition switch (X274) is in position I or II. The CD Changer (Z114) is permanently supplied with power through the P wire via the radio and a DIN cable. The high line (NAS/JAPAN) radio has the following features: Electronically tuned AM/FM cassette radio (Z111), RH antenna amplifier (Z178) for AM/FM signals, LH antenna amplifier (Z177) for FM signals only, a subwoofer amplifier (Z176), a CD changer (Z114) a Digital Signal Processor (DSP) amplifier (Z293) and 10 speakers plus a subwoofer speaker (K146).

Subwoofer

The subwoofer amplifies frequencies between 20 and 150 Hz to give an enhanced bass sound.

Subwoofer Amplifier

The subwoofer (K146) is supplied with power and ground from the Subwoofer Amplifier (Z176) via two separate channels which consist of 4 BW/B wires. The subwoofer amplifier (Z176) is permanently switched on when the radio supplies a signal on the SB wire.

Speaker Amplifier

The DSP amplifier (Z293) is located behind the LH rear luggage compartment behind the subwoofer. The DSP amplifier (Z293) now incorporates the door amplifiers which are no longer fitted separately. Navigation information is supplied to the DSP amplifier (Z293) which outputs the information to the relevant speaker(s).