Wx No Good - Radio Shack TRC-447 Service Manual

PLL CIRCUIT

WX No good

Check
the voltage of
TP4 approx. 1 to 4V
at CH1~7.
OK
Check whether
each CH frequency matches
the frequency indicated in
frequency chart.
OK
Good PLL is not defective.
NG
Check
the voltage
reading at pin 15 of
IC301 is approx.
5 V.
OK
Check if there is RF
voltage at pin 16
of IC301.
OK
Check the voltage Q305.
OK
whether there is a
NG pulse at pins 13 and 14 of IC401
when rotating the CH rotary
SW top side and
down side.
NG
Defective Vcc line at R316
or D303.
NG
Defective xtal X301 or poor
soldering.
NG
Defective Q305.
Check
NG
OK
— 13 —
Check the soldering
between main and front wires
or check the channel switch.
OK