Kenwood TK-885, Service Manual

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35
TK-885
Ref. No. Use / Function Operation / Condition
IC508 Shift register LR, LG, KBLC, MM1, T/R, KEY,
BSFT, PA2 output
IC509 Reset Low voltage output when powering up
IC510 Flash ROM
IC511 CPU
IC512 EEPROM
IC513 5V AVR 5C (Control unit)
IC710 Buffer amp HSD
IC711 Buffer amp MIC
Q501 MIC mute Active while MM is “H” and MM1 is “H”
Q502 AF mute Active while KEY is “H”
Q503 Noise amp
Q507 Inverter PA2 H/L switch
Q508 LED switch (Green) Active while LG is “H”, active while RX
Q509 LED switch (Red) Active while LR is “H”, active while TX
Q510 Clock switch shift Clock shift is on while BSFT is “H”
Q511 FSW swtich Foot switch is on while FSW is “L”
Q512,513 Key backlight switch Active while KBLC is “H”
Q515 Key backlight switch
D501 Surge absorption BLC
D502 Over current PSB
protection
D503 Surge absorption CM
D504 Surge absorption PTT/TXD
D505 Surge absorption HOOK/RXD
D507 MIC mute MM/MM1
D508 Limiter MIC
D509 Limiter ASQ
D510 Reverse current C575 charge
protection
D511 BUSY/TX LED Lights green while busy, red while TX
D512~517 Key backlight Active while KBLC is “H”
D518 Current regulation Key backlight
D520 Discharge Speed up
VCO Unit (X58-4723-01)
Ref. No. Use / Function Operation / Condition
Q101 Oscillator RX
Q102 Inverter Active while ST is “H”, active while TX
Q103 Oscillator TX
Q104 TX/RX switch Active while ST is “H”, active while TX
Q105 TX/RX switch Active while Q102 is off
Q106 Buffer amp
D101 RX VCO
D102 TX VCO
D103 RX VCO
D104 TX VCO
D105 Modulation
SUB Unit (X58-4850-11)
Ref. No. Use / Function Operation / Condition
Q1 Ripple filter 9CL
DESCRIPTION OF COMPONENTS /