Kenwood TK-80 Service Manual page 30

Ref. No. Use / Function
D45 LED Voltage limiter
D47 Reverse flow
prevention
D48 PIN diode Diode of 10.695MHz level variability
D49 Reverse flow
prevention
D50,51 Switching ON in transmit
D52,53 Detection SSB, CW envelope detection
D54 Detection AM envelope detection
D55 Detection AGC squelch detection
D56 Switching ON in transmit
D59 Detection Detection of MIC amplifier output
D60,61,63 Reverse flow
prevention
D64 Rectification DC/DC converter
D65 Zener diode For constant voltage
D66 Surge absorption Protect for transistor of linear
amplifier control
D67 LED Voltage limiting
D68 Zener diode 3.6V voltage shift
D69,70 Reverse flow
prevention
COMPONENTS DESCRIPTION
Operation / Condition Ref. No. Use / Function
D71 Zener diode 12V voltage shift
D72,73 Reverse flow
prevention
D75 Zener diode Reduce the output power when
power supply voltage drop
D76,79 Reverse flow
prevention
D80 Zener diode Reduce the output power when
power supply voltage drop
D81~87 Reverse flow
prevention
D88 Zener diode Over voltage protection
D500,501 Switching DDS register selection
D502 Vari-cap VCO1
D503 Switching VCO1 output
D504 Vari-cap VCO2
D505 Switching VCO2 output
D506 Vari-cap VCO3
D507 Switching VCO3 output
D800 Detection Noise detection
D900~902 Reverse flow
prevention
TK-80
Operation / Condition
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