ERICSSON EF738 SERVIS INSTRUCTIONS

Service Instructions

Ericsson Mobile Phone EF738

Service Instructions

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Service Instructions

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Contents

System Connector Signals ____________________________ 5
Disassembly________________________________________ 6
Reassembly ________________________________________ 7

Flip Mount Inspection______________________________________ 8
Warranty Seal ____________________________________________ 8

Exchanging the Circuit Board_________________________ 9
Fault Findin

Sequence of Adjustments __________________________________ 11

Item 1: VCTCXO ____________________________________________ 11
Item 2: RSSI Calibration ______________________________________ 12
Item 3: RF Output Power ______________________________________ 13
Item 4: Maximum Deviation ___________________________________ 14
Item 5: Nominal Deviation_____________________________________ 15
Item 6: SAT Deviation ________________________________________ 16
Item 7: TX Data Deviation_____________________________________ 17
Item 8: AFMS and Harmonic Distortion __________________________ 18
Item 9: Receiver Sensitivity ____________________________________ 19

and Alignment ________________________ 10

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Service Instructions

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System Connector Signals

External units are connected to the Transceiver Board via the 12-pin System Con­nector.

12 3 11 12

Pin Signal In/Out Function

1 AFMS Out Audio From Mobile Station

Service Instructions

2 ATMS In Audio To Mobile Station
3 EXTAUD In External Analog Audio Accessory Sense
4 AGND Audio Signal Ground, 0V reference
5 PORTHF In Portable Handsfree
6 MUTE Out Music Mute
7 VPPFLASH In Flash Memory Voltage and Service Voltage
8 VDD Out Logic Reference, Status ON
9 DFMS Out Data From Mobile Station
10 GND Digital Ground and DC Return
11 DTMS In Data To Mobile Station
12 DCIO In/Out DC positive pole for phone battery charging

and external accesso ry powering

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Service Instructions

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Disassembl

1. Remove the battery and the antenna
Before opening the unit for further disassembly, make sure that the parts can be
placed on a

NOTE!

2. Place the phone on its front and remove four screws with the appropriate torx
screwdrivers.

3. Remove the back cover carefully from underneath.

4. Loosen the remaining screws (6, 10).
Be careful not to damage the antenna connector (7).

5. Careful ly remove the board (1) from the front cover (2) by lifting it upwards.

6. Remove the keypad (4).

dust-free ESD-protected surface

Do not

touch the display with your fingers!

.

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