User's Manual

24
8.3 VCO Trouble
Rx VCO TX VCO
Check the VCO control voltage
(L151) when the VCO output
(C148) level is low or zero.
Check the VCO control voltage
(L152) when the transmission
output (C148) level is low or
zero.
↓ ↓
Carefully disassemble the VCO
shield can, and perform visual
inspection. Is the VCO shield
can normal?
No
→
Take proper actions.
No
←
Carefully disassemble the VCO
shield can, and perform visual
inspection. Is the VCO shield
can normal?
Yes↓ Yes↓
Are bias voltages of Q102 and
Q104 normal?
No
→
Check parts of the
power supply circuits
of Q33 and Q34.
No
←
Are bias voltages of Q103 and
Q104 normal?
Yes↓ Yes↓
Check if the bias voltage of
the C130 is 5V. (VTVM)
No
→
Check devices around
Q33, Q34, and U601.
No
←
Check if the bias voltage of
the C140 is 5V. (VTVM)
Yes↓ Yes↓
Is the control input voltage (L151) of
PF-100NW between 0.3 and 4.4V?
(VTVM)
Is the control input voltage (L152)
of PF-100NW between 0.3 and
4.4V? (VTVM)
Yes↓ No↓ ↓ No Yes↓
Normal
Adjust the C123 and the C132 to maintain
the voltage.
Normal