TC- 446 Service Manual
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37
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Y
Y
Start
Correct software mode settings and freq range?
TX unlock: TX unlock on
some channels?
RX unlock: RX unlock on
some channels?
No TX CV
TX CV: > 4V
or < 0.8V?
Check synthesized
sector;
Bias (pin C 4V)
at Q16 OK?
Adjust TC1; reliable
solder & correct
parameters of C182,
C193, C95, L44,
C192, C90, L5, D4?
Adjust TC2; reliable
solder & correct
parameters of C186,
C187, L46, R69,
L16, C19, C188,
L48, D8, D7, L17?
Check synthesized
sector;
RX CV: > 4V
or < 0.2V?
Bias (pin C 4V)
at Q8 OK?
4.1V output
voltage at Q7?
Reliable solder and correct
parameters of R164, R9, L47, Q8 ?
In RX, 4.3V at
IC11 pin 31?
Check IC11,
peripheral
components; or
replace IC11.
Reliable solder
at Q7, R53; No
disconnected
wiring to branch
circuit?
4V output
voltage at
Q6
?
Reliable solder at
R171? No
disconnected wiring to
Q16 branch circuit?
In TX, 0V at
IC11 pin31?
Reliable solder at PTT?
No disconnected wiring
to IC11branch circuit?
Or replace IC11.
Check the value and soldering
of
Q6
、
R9. Replace faulty
components.
Check R11, L19, R74, Q13;
Replace faulty components.
Voltage at
TX
CV?
Voltage at
RX
CV?
Adjust TC2
Adjust TC1
Adjust to freq band/freq
set in the radio;
N
Y
N
N
Y
N
Y
Y
N
No RX CV
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
N
Y
N
N
Summary of Contents for TC-446
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