User's Manual

22
Is the sensitivity -120dBm?
No
→
Check XFL301/302 and other
devices around Q303.
Yes↓
Send 21.4 MHz to Pin No. 6 of
U101. (SSG)
Check T-TAL filter and other
parts of XFL301/302.
↓ Yes↑
Is 21.4MHz sensitivity around
–98dBm?
Yes
→
Is the bias of each end of
Q303 normal? (VTVM)
No
→
Check the IFIC Q303
amplifier, RX 5V,
power supply, and parts.
No↓
No
→
Replace the IF U101.
Does the sub-oscillator of the
secondary station (20.945MHz)
in the X301 oscillate?
(Scope, Counter)
No
→
Is the voltage at Pin 4 of the
IF U101 normal? (VTVM)
Yes↓ Yes↓
Check voltages at each pin of
the IF U101. (VTVM)
Replace X-TAL and other parts
of the sub-oscillator of the
secondary station in X301.
Yes↓
Is the voltage at each pin
normal? (VTVM)
Yes
→
Check connection parts of the
IF U101.
No↓
Check IF U101 and parts,
and replace IF U101 if needed.