Raymarine RAY 210VHF Operation Manual page 47

Item
Number
4 Squelch circuit inoperative a. Check squelch control
5 No receive (RX)
6 Low receiver frequency
7 CPU inoperative [CPU AF
Board]
8 Display malfunction
[CPU AF Board]
Table 5-4 (Continued)
Symptom
35
Possible cause
b. Defective IC307 and/or associated
circuitry between pins 7 and 9
a. Defective regulators 1C 15(5V) and 1C
17 (8V)
b. Defective Q33 (KXB+)
c. Check IC 307 audio output voltage at
pin9
d. Defective AF amplifier IC 305
e. Defective mute circuitry (Q6 IC1)
[CPU AF Board]
f. Check XTAL4 output for 21.145MHz
signal
g. Check 21.6MHz output of first mixer
Q23, D15, DIG
h. Check 21.6MHz output of ceramic
filter FIL101
i. Check 21.6MHz output of first IF
amplifier Q30
j. Check 455 kHz signal from ceramic
filter FIL3
k. Failure of VCO circuit (Q13, Q15, Q17
and/or PLL IC9)
l. Defective CPU (IC1) [CPU AF Board]
a. Check antenna and connector for
possible corrosion or bad connection
b. Failure of the output from Q21, Q22,
Q30 and/or IC307
c. Check the output level of VCO per
para.5.3.1
a. Turn off the power once, and try again
b. Check CPU clock frequencies (pins 36
and 37 of IC1)
c. If clock frequency is not present, check
for +5VDCline(IC4)
a. Check the interconnection to the LCD
display
b. Inoperative CPU