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Q120 TV Maintenance Manual
5
frequency discrimination to this signal and the mixed signal of TXVCO signal and
RFVCO output signal. The discriminator outputs the signal control RFVCO and
RFVCO phase is enabled to lock at the phase of TXIF signal. TXVCO output RF is
still decided by RFVCO frequency. The phases of RFVCO and IFVCO signals lock at
the phase of VCTXO reference signal. The TX signal outputted by U102 pin 11/12 is
transmitted to the antenna via antenna switch to launch.
1.4 Base band circuit
Base Band adopts MT6252A/B. .
MT6252 internal schematic block diagram
Summary of Contents for Q120 TV
Page 3: ...Q120 TV Maintenance Manual 3 1 Circuit diagram instruction 1 1 Main board explored view...
Page 6: ...Q120 TV Maintenance Manual 6 1 5 Function circuit FM circuit U802 FM receiving chip RDA5802E...
Page 7: ...Q120 TV Maintenance Manual 7 BT circuit U701 BT receiver chip MT6612CN L...
Page 10: ...Q120 TV Maintenance Manual 10 3 2 No ring tone...
Page 11: ...Q120 TV Maintenance Manual 11 3 3 LCD display fault...
Page 12: ...Q120 TV Maintenance Manual 12 3 4 Charging fault...
Page 14: ...Q120 TV Maintenance Manual 14 3 6 Fail to identify SIM card...
Page 15: ...Q120 TV Maintenance Manual 15 3 7 MIC fault...
Page 18: ...Q120 TV Maintenance Manual 18 3 10 Vibrate fault...
Page 19: ...Q120 TV Maintenance Manual 19 3 11 FM fault...
Page 23: ...Q120 TV Maintenance Manual 23 3 15 Unable to use USB END...