Lenovo i909 Bakım Kılavuzu - Sayfa 24
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I908 Mobile Phone Maintenance Manual
Problem 3:
Problem: After several times of calibration, the output power is still higher than normal. And
then PA is damaged.
Cause of the Problem: PA and chips of VAPC input assemblies are out of position. PA is
damaged.
Solution:
4.3 Testing of the Unit/Problems during Repair
4.3.1 Switch Spectrum and Ramp Mask overrun
Problem: The switch spectrums and ramp masks of both GSM and DCS bands exceed the
limits.
Cause of the Problem: If R2103 (10K Ohm), R2104 (18K Ohm) or the capacitor C2105 (220pF)
on the V_ ramp signal cable of the PA are not soldered properly or damaged, this will cause
the frequency and spectrum to exceed norms.
Solution:
After several times of
calibration, the output
Is the voltage of PA (U2102) at Pin6 far
higher than 1.4V?
Are the upper parts of
and
C2105
PA may be damaged. Replace
C2105, R2104 and PA (U2104). Then
Switch
and Ramp Mask
Does the voltage of PA (U2102) at Pin6 falls
within the normal range (less than 1.8V)?
Check C2105 and R2104
(critical point) for possible
Replace elements with
pseudo soldering.
LENOVO
N
Y
N
Replace
R2104
(U2108)
Spectrum
Page 24
Replace
PA
(U2102)
and
repeat
PA
and