Electric Unit (X25-91Xx-Xx); Component Description - Kenwood KDC-8021 Service Manual

ELECTRIC UNIT (X25-91xx-xx)

Element Purpose & Function
IC1 System uCOM
IC2 E.Vol & N.C. MPX
IC3 Power Supply IC
IC4 POWER IC
IC5 HPF & LPF & NON-FAD SW
IC6 CD mechanism 4.7 V power SW-Reg.
IC7 4.5 V PRE-OUT DC/DC
IC8 RESET IC
IC9 Muting logic IC
IC10 Spectrum analyzer opamp
IC11 4.5 V PRE-OUT opamp
IC12 4.5 V PRE-OUT opamp
IC13 4.5 V PRE-OUT opamp
IC14 RDS decoder
IC15 Motor Dr. IC
IC16 E2PROM
Q1,2 BU 5V AVR
Q3 SW 5V
Q4,5 SW 14V
Q6,7 AUDIO 8V AVR ON/OFF SW
Q8 AUDIO 8V AVR
Q9 Servo power AVR
Q10 CD 4.7V SW-Reg ON/OFF SW
Q11,12 FL & ILLUM AVR ON/OFF SW
Q13,14 FL & ILLUM AVR ON/OFF SW
Q15,16 4.5 V PRE-OUT DC/DC converter AVR
Q17~22 Regulated power supply Tr.
Q23,24 POWER-ANT SW
Q25,28 POWER-CONT SW
Q26,27 POWER-CONT circuit output protection
Q29 External amp control SW
Q30 Dimmer control SW
Q31 B-U detection
Q32 Acc detection
Q33 Lch MUTE Dr
Q34 Rch MUTE Dr
Q35 Spectrum analyzer AGC Tr.
Q36 E-Vol muting SW
Q37 Noise buffer
Q38 AUDIO MUTE SW
Q39 AUDIO MUTE SW
Q40 AUDIO MUTE SW
Q41 AUDIO MUTE SW
Q42 AUDIO MUTE SW
Q43 AUDIO MUTE SW
Q45,46 FM+B SW
Q47,48 AM+B SW
Q49 Composite signal buffer
Q50 PANEL 5V SW

COMPONENT DESCRIPTION

Error detection in combination with Q8. Audio 8 V AVR drive.
50Wx4ch
"L" when Mask uCOM detection voltage is 3.7 V or less or
when Flash uCOM detection voltage is 4.2 V or less.
4 inputs. NOR gate x 4.
Front output.
Rear output
Non-Fad. output
For storage mechanism
Darlington connected.
ON when the base is "L".
Turns Q7 ON when the base of Q5 is "H".
8 V ON/OFF SW. Q7 turns ON when the base of Q6 is "H".
CD 4.7 V SW-Reg ON/OFF SW. ON when the base is "H".
FL & ILLUM AVR ON/OFF SW.
Q12 turns ON when the base of Q11 is "H".
Darlington connected.
Q24 turns ON when the base of Q23 is "H".
Q25 turns ON when the base of Q28 is "H".
Upon detection of drop in the output voltage, these transistors turn
Q25 OFF to protect the output. This prevents malfunction of Q26 when
the POWER-CONT SW turns ON.
Turns ON when a pulse is input to the base.
Small In is detected when the base is "H".
"L" when B-U is present. "H" when B-U is absent or momentary power
down is detected."
"L" when Acc is present.
L-ch audio muting SW drive. ON when the base is "L".
R-ch audio muting SW drive. ON when the base is "L".
When the base is "L", turns ON to mute E-Vol.
Mutes the Front R CH hen the base is "H".
Mutes the Front L CH hen the base is "H".
Mutes the Rear R CH hen the base is "H".
Mutes the Rear L CH hen the base is "H".
Mutes the Non-FAD R CH hen the base is "H".
Mutes the Non-FAD L CH hen the base is "H".
Q46 turns ON when the base of Q45 is "H".
Q48 turns ON when the base of Q47 is "H".
When the panel is attached, the base goes "L", turning the transistor
ON to supply 5 V to the panel.
KDC-8021/M9021/X859
Operation, Condition, Compatibility
3