User's Manual

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TROUBLESHOOTING GUIDE
SYMPTOM S CAUSES COUNTERMEASURES
Unit does not work
1.No power incomplete
connection
2. No input voltage of 5V or 8V
3. CPU does not work
4. EEPROM fail
5. Channel error
6. PLL error
1.Check COM1 connection
2. Check IC500、IC504
3. Check IC510
4. Check IC502
5. Check CF3
6. Check TCXO、VCO、PLL IC
Bad RX Sensitivity
1.Antenna signal short-circuit
2.Antenna signal open-circuit
3. Bad
electronic turner
4. Defective high frequency
amplifier
5. Bad mixer
6. Local signal amplitude
become small
7. Bad 1
st
and 2
nd
intermediate
frequency
1. Check D106 D107
2. Antenna loose weld
3. Check L23 L24 L25 L26
4. Replace Q15
5. Check IC3 T3 T4
6. Check D103 Q111
7. Check XF1 XF2 IC2
Defective RX
1. No output signal
2. Bad signal waveform
3. Bad stability of VCO
1. Replace IC801
2. Check U2 c412 c404
3. Check component of VCO
PLL Error
1. TCXO frequency error
2. Bad stability of VCO
3. PLL can’t be locked
1.Check crystal oscillator of TCXO
2.Check the component of
TX/RXVCO
3. IC301 Q321 Q320 C327
Low TX Power 1. Bad amplifier circuit
2. Bad APC circuit
1. Replace IC102
2. Check D102 IC1
No TX Power
1. No power on TX
2. No signal on driver
3. Bad amplifier circuit
4. Bad APC circuit
1. Check Q502 Q503
2. Check Q1 Q2 D101
3. Check IC102 D102
4. Check IC1
No Modulation 1. No input signal
2. No TX signal
1. Check IC801
2. Check U1 R403 R404