Components Description - Kenwood KRC-21SA Service Manual

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SYNTHESIZER UNIT (X16-149x-xx)
Ref.No. Application/Functions
IC1 LCD driver with key-matrix
Q1 Key-matrix permission SW
SYNTHESIZER UNIT (X14-685x-xx)
Ref.No. Application/Functions
IC1 System MI-COM.
IC2 E-VOL. & N.C. MPX
IC3 Mute logic
IC4 Power IC
IC5 Equalizer amplifier
BACK-UP detection(Momentary
Q50
power down detection) SW
Q51
BACK-UP 5V AVR
Q52
Q53 P.ON 5V SW
Q54
COM+B SW
Q55
Q56
COM+B AVR
Q57
Q58
Illumination +B SW
Q59
TE
Q60
L 13942296513
Illumination +B AVR
Q61
Q150 Electric volume mute SW
Q151 SVR discharge SW
Q153 Pre-out mute driver
Q200
FM +B SW
Q201
Q202
AM +B SW
Q203
Q260
Motor +B SW
Q261
Q301 Changer reset SW
Q320 Panel 5V SW
Q350 P-CON. driver
Q351 P-CON. protection SW
Q352 P-CON. protection inhibit SW
Q353 P-CON. SW
Q370
ANT-CON. SW
Q371
Q450 Pre-out mute SW (R ch.)
Q451 Pre-out mute SW (L ch.)
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COMPONENTS DESCRIPTION

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Operation/Condition/Compatibility
Ready on key-matrix
Operation/Condition/Compatibility
System control
Controls sound volume. Selects each source.
3-input NOR gate x 3
Amplifies power so that the speaker can drive audio signal.
Equalizer amplifier for cassette tape sound
While BACK-UP is added, a base becomes Hi, and Q50 is turned on.
While BACK-UP is added, AVR outputs +5V.
Q51 and Q52 is inverted Darlington connection.
While a base becomes Lo, Q53 is turned on.
While Q54's base becomes Hi, Q55 is turned on.
Works during POWER ON mode.
While Q57's base becomes Hi, Q56 is turned on.
Q56 and Q57 is inverted Darlington connection.
While Q58's base becomes Hi, Q59 is turned on.
Works during POWER ON mode with a panel attached to the set.
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3 6 7 1 3
While Q61's base becomes Hi, Q60 is turned on.
Q60 and Q61 is inverted Darlington connection.
When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
works, a base becomes Hi, and Q150 is turned on.
When POWER IC RESET is activated, a base becomes Hi, Q151 is turned on.
When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
works, a base becomes Lo, and Q153 is turned on.
Q201 is turned on when Q200's base becomes Hi.
Works during FM reception mode.
Q203 is turned on when Q202's base becomes Hi.
Works during AM reception mode.
When Q260's base becomes Hi, Q261 is turned on. Works during TAPE mode.
When a base becomes Lo, Q301 is turned on.
While a panel is attached to the set, a base becomes Lo, and Q320 is turned on.
When Q353's base becomes Hi, Q350 is turned on.
Works when P-CON is being short-circuited on GND.
Inhibits protection SW function when P-CON works momentary.
Q353 is turned on when a base becomes Hi. Works during POWER ON mode.
Q370 is turned on when Q371's base becomes Hi.Works during TUNER mode.
When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
works, a base becomes Hi, and Q450,451 are turned on.
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KRC-21SA/SG/SYA/SYG
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1 5 0 5 8 2 9 9 4
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KRC-266/S
9 9
2 8 9 9
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