LG CE500, Service Manual

Page: 72 / 127

4. TROUBLE SHOOTING
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Checking FEM & Mobile Switch
3) Check RF frequency at each point(1,2,3,4,5).
Can you observe good RF signal at proper
frequency?
• GSM850 190Ch. : 881.6MHz
• GSM1800 700Ch. : 1652.8MHz
• GSM1900 661Ch. : 1960MHz
4) Check RF Power at each point.
Can you observe good RF signal at proper
frequency?
At check point 1& 2
→
RF Power is almost same with input power set to
equipment.
If not, change FL701(Mobile SW)
5) At other check point
→
GSM850 Insertion loss ~ 2.8dB
→
GSM1800 Insertion loss ~ 3.4dB
→
GSM1900 Insertion loss ~ 3.4dB
If not, change FL701(Ant. SW)
1
2
3 4 5
FL701
Check these circuit with High Frequency
Probe at each point.
You can see RF signal at Spectrum
Analyzer.
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