Can startup and shutdown,

The fault is also one of the common faults. It involves many units. When receiving, firing, frequency synthesizer, BB processing, CPU, software problems, can cause such failures.
Examination and treatment:
. Antenna contact well? Treatment methods: The ethanol wash, calibration antenna reed.
. Check the RF and IF frequency synthesizers, RFVCO, IFVCO working voltage? Is there a cold solder joint?
. Check the receiver front-end LNA (low noise amplifier) operating point? Whether cold solder joint?
. RFSAW or IFSAW check whether the deterioration of the performance? Whether or cold solder joint? Available 100P capacitor jumper give it a try.
. Check RFIC operating voltage? Whether or cold solder joint?
. Check the I / Q Quadrature MODEM operating voltage normal? Generally normal for the: DC1.2V about single-ended AC500mVpp around.
. Check the BB processing unit operating voltage? Whether or cold solder joint?
. Check launches VCO, PA, MOS switch, APC control circuit have any questions? Whether or cold solder joint? This is a typical point of failure.
. For the early models, need to check the connectors between the RF and the BB whether or cold solder joint?
. Repair welding CPU, re-write the software.

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