Kenwood TKR-740 Service Manual page 31

3.4 APC circuit
The APC circuit consists of differential amplifier IC302 (B/
2), DC amplifier Q301, and sw itching transistors Q304. The
pow er setting range in the high-pow er mode is 25 W; the
pow er setting range in the low -pow er mode is 5 W.
Fig.11 APC circuit
3.5 High temperature detector circuit
The high temperature detector circuit consists of thermal
sw itch TS301 and sw itching transistor Q302. This circuit
disables the transmitter pow er amplifier to protect the circuits
w hen the final unit temperature is too high (95 ˚C or higher)
and the circuit cannot be operated safely.
Fig.12 High temperature detector circuit
CIRCUIT DESCRIPTION
3.6 Common mode spurious filter circuit
the final unit to reduce common mode radiation from the power
cable.
The TKR-740 has a filter L304 at the DC pow er line inlet in
Fig.13 Common mode spurious filter circuit
TKR-740
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