Asus M930 Service Manual download pdf (Page 38)

GTC Service Manual

ASUS Proprietary 38

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碩

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腦

10.2

10.2 10.2

10.2 GSM/GPRS

GSM/GPRSGSM/GPRS

GSM/GPRS/EDGE

/EDGE /EDGE

/EDGE Test & Repair Procedure

Test & Repair ProcedureTest & Repair Procedure

Test & Repair Procedure

How RF signal is transmitted and received between components on M930 PCB

will be explained in this section. It is important to realize RF transmission path

(Tx) and receiving path (Rx) before starting out to repair NG PCB, because

engineers need to choose proper test points which assist us to catch the signal

quickly

Before beginning to repair, because we have no way of knowing questions. So

in the beginning, I will refer the normal RF performance characteristics.

According to these descriptions, we can sort out various problems directly.

In GSM part, including several important components mainly, for instance:

Front End Module (SKY77513), GSM 4-band transceiver RF3000, Rx filter,

and 26MHz Crystal etc. First of all, I will explain the working state of a normal

FEM including its test points. You can analysis it according to the result.

When a phone is connected with the Agilent 8960 tester, There have 3 modes

during the normal working state (Fig1)：R (Receiver), T (Transmission), M

(Monitor). According to truth table of the circuit diagram, we can judge whether

this FEM operates normally or not.

In GSM900 TX mode (Power Level 5 ) as an example：

1.Check these four components on below diagram (BS1：C830, BS2：C825,

TX_EN：C831, and Vapc：R822)

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Asus M930 Service Manual Page 38