User's Manual

21
8. Troubleshooting Flow
8.1 Reception Trouble
Start
↓
Reception is not made.
↓
No No
→ →
Check IF U101 and
the peripheral devices.
Press Monitor button. Is sound
heard from the speaker?
Is there any signal or noise in
Pin No. 9 of IF U101? (Scope)
Yes↓ Ye s↓
Check AF U505, U508B, U506,
and the peripheral devices.
Measure G2 pin of the mixer
(Q302). Is the local level –
3dBm? (Measure the local signal.)
No
→
Check the Rx bias (Q105). → Check the Rx VCO end.
Yes↓
Send the currently received
frequency to the C351.
↓
Send the corresponding channel
frequency to the C300.
↓
Is the sensitivity -110dBm at
12dB SINAD?
(Scope, SINAD meter)
Yes
→
Is the sensitivity -118dBm?
No
→
Are collector voltages of
Q301 and Q308 around
3.7V?
No↓ ↓ No↓
Check the harmonic filter and
the antenna connection part.
The sensitivity should be more
than -110dBm.
A trouble in the front end
Replace the IF 21.4MHz with
the C1000p, not the R318, and
input 21.4MHz frequency.
(RF SSG)
↓