Lenovo S960 Service Manual - Page 29
Browse online or download pdf Service Manual for Cell Phone Lenovo S960. Lenovo S960 37 pages.
Also for Lenovo S960: Quick Start Manual (6 pages), Schematic Diagrams (10 pages)
Print Page
LENOVO S960 Cellphone Service Manual
Problem: The device can turn on and receive signals normally. But there's no power output or
power output is very low, when it is trying to output power of double frequency bands or single
frequency band.
Reason: Many factors can cause no or low power output, such as when Transceiver output circuit,
PA module input/output circuit, antenna connectors and antenna switch control signals or power
feeding circuits have a problem. In particular:
RF connector (CON2201)
Check whether connections between RF connector CON2201 and test probes of RF test
cable are reliable; patches are fixed in the correct direction; or antenna connectors
are damaged.
Solution: Replace antenna connectors and ensure patches are in the correct
direction.
RF power amplifier (U2201)
Whether PA's control signal PA_ENABLE (Pin17) is at high level (about
A．
2.8V); If it is at low level, PA will have no output;
PA's power feeding pins Pin13, pin14; check whether power feeding voltage falls
B．
into normal range (normally 3.6V～4.2V);
Check whether PA's RF input
C．
problems;
Whether PA's RF input C2210 and C2211 have dry joint problems;
D．
PA's V_ramp control signal circuit: If C2209 has a dry joint or circuit break
E．
problem, PA's output power will be abnormal.
Transceiver (U2105)
Check whether power feeding voltage of Transceiver (U2105) falls into the normal
A．
range. You can check power feeding voltage at the place where power feeding
filter capacitor and U2105 are connected. Then check whether peripheral
circuits have dry joint problems.
Whether dry joint or short circuit problems exist on Transceiver (U2105) and its RF
B．
output matching circuits.
If it's permitted by whole-unit service terms and conditions, you can put the cell
phone into constant-emission status of maximum power. Then detect power output of each
module in the emission channel with probes from a spectrum analyzer. In normal
circumstances,
A．
you can detect a power output about GSM 33dBm or DCS/PCS 30dBm at the output
end of the RF connector;
B．
you can detect a power output about 32dBm or 29dBm at the place where PA output
end pin26 is connected;
4.3 WCDMA calibration during production
4.2.4 Power output related problems
,
C2208
Page 29
,
and
R2209
C2207
R2203
have dry joint