NEC N8 User manual

N8
Service Manual
(Level 3)

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Introduction
This is the Electronic Service Manual for the N8 Tri Band GSM Digital
Cellular Telephone from NEC. It contains specific information on repair and test
procedures.
For details of user functions, general operation and installation, please
refer to the User Guide.
The Service Manual is set out in the following sections.
1. Precautions for Repair Work: provides general guidelines for
undertaking safe and efficient repair work.
2. Unit Specification: provides the technical specifications for the
N8 GSM Digital Cellular Telephone.
3. Introduction of Service Level:
a) Service Level 1:describes definition of Service Level 1, equipment and
tools required for this level.
b) Service Level 2:describes definition, equipment and tools required for
Service Level 2.
4. Circuit Description: provides functional details of the circuits, block
diagrams and component purpose descriptions.
5. Servicing : defines the jigs, fixtures and test configurations required for
servicing the product; and describes the processes of assembly and
disassembly.
6. Troubleshooting : provides an aid to fault finding the product. Includes,
using the signal levels and plots at various parts of the circuit.
7. Device Information : provides functional information and pin-outs of most of
the semiconductor devices within the HHP.
8. Circuit Diagrams : contains all the schematics diagrams.
9. Board Maps : contains all component layout diagrams.
10. Parts List : provides information for the ordering of replacement parts.
11. Glossary : terms used in this manual.

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Section 1
Precautions
for Repair Work
1

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Important
Please read the following cautions, notes and warnings
before progressing through this manual or undertaking
any repair action.
Remember: SAFETY FIRST!
CAUTION:
AC Power Cord:
Care must be taken not to damage the AC power cord as fire or electric shock may
result.
Battery Pack:
Only use the specified batteries and chargers with this equipment.
Do not short the battery terminals together.
Keep the battery pack away from fire and sources of ignition.
Remember to recharge the battery pack after each use.
Before Powering up the Equipment:
•Only switch on the telephone’s power once the test or installation set-up is complete.
•Switching on at the wrong time may result in electric shock or damage to system
components.
•Always ensure that the power is switched off before making connections /
disconnection’s.
•It is important to check that the correct DC voltage is applied to the equipment to
prevent electrical damage.
Component Polarity:
Always check the polarity of connections and components before soldering. Particular
attention must be paid to IC.s, diodes, transistors, capacitors and any other
semiconductor device that is polarity dependent.
Electrostatic Damage (ESD):

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Semiconductor devices are easily damaged by electrostatic discharge. Many of the
procedures detailed in this manual involve disassembly of the equipment and therefore
handling of the printed circuit boards.
To protect these devices from ESD a wrist strap connected to ground must be worn. In
addition to this the work surface must be covered with an anti-electrostatic mat, which
should also be grounded.
If printed circuit boards are to be stored without being re-assembled into their
equipment, then they must be kept in an anti-electrostatic bag.
Grounding:
Each piece of test equipment should be electrically grounded. A third (grounding) pin is
provided as a safety feature. Ensure that the electrical outlet also contains this feature.
Cosmetic Protection during Repair Work:
Always ensure that the working surface is kept clean and free from abrasive materials.
The LCD is very susceptible to scratches and damage. It should be covered with clear
adhesive vinyl while the equipment is disassembled.
Storage of Faulty Components:
Any components that are replaced due to failure should be kept safely in an anti-
electrostatic container. NEC’s Quality or Research & Development Departments may
require them to make quality and reliability investigations.
No Fault Found Equipment:
In some cases the reported symptom may not be apparent. You may subject the
equipment to a controlled amount of stress, vibration and temperature variation to see
if the fault occurs.
Care should be taken not to apply excessive stress or vibration or extreme temperature
variations as further faults may develop.
Soldering and Disordering :
Fast, accurate and high quality soldering is required to minimise the risk of heat damage
to the electronic components.
The soldering tip should not be in contact with components or PCB tracks for longer than
2 seconds.
Heat the pad on the PCB and the lead, quickly apply solder, remove heat and cool.
After soldering is complete, ensure that all solder joints are of good quality - no dry
joints, solder bridges, cracks or excess solder.

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The majority of chip components are machine mounted using solder paste. Removal of
the solder is not sufficient for chip component removal. Each solder point must be
heated simultaneously and quickly (to prevent component and PCB damage). When the
solder has melted, remove the component with tweezers.
Short Circuits:
Care must be taken to avoid short circuits. Soldering, solder dust, screws, metal
clippings, metal wrist watches etc. can cause short circuits on PCBs which may result in
component damage.
Test Equipment Calibration:
Your test equipment should be calibrated before use. Frequent calibration is essential
to ensure high quality and reliable repairs.
Cleaning:
Before cleaning ensure that the telephone is switched off and disconnected from the
power source. Cleaning should be done using a soft dry cloth. If the equipment is
heavily soiled a soft cloth soaked in a mild synthetic detergent diluted in water may be
used.
Never use benzene or any other chemicals to clean the equipment.
RF Shielding:
It is advisable to carry out detailed measurements and repair (in particular RX) in a
shielded area to minimise RF interference.
AC Adapter and Battery Charger:
The AC adapter and battery chargers are for indoor use only. Ensure that the devices
are not exposed to rain or moisture.
Electrical Safety:
Electrical equipment is hazardous if misused. Any repairs must be carried out with care
and only by authorised personnel.
Ensure all power sources are switched off and power cords removed before undertaking
any repairs.

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Hazardous Waste:
The battery pack, if incorrectly disposed of, is an environmental hazard. It must be
disposed of in accordance with the regulations of the country concerned.
Never dispose of the battery pack in fire or water.
Confidentiality:
The circuitry within this equipment contains several components that are regarded as
company confidential. Only use NEC specified parts as replacements.
RF Injury:
To avoid RF injury, direct exposure to radio frequency energy should be avoided. In
particular, exposed parts of your body (especially the eyes and face) should not come
into contact with the antenna while the equipment is transmitting.
Storage Conditions:
It is recommended that the following storage conditions should be avoided to prevent
damage to the equipment: -
Dusty.
Humid.
Near to magnetic equipment
In direct sunlight
.
Ventilation:
Repair areas should be well ventilated and fume extraction systems should be installed
where necessary. Potential hazardous substances are solder fumes, flux, alcohol etc.
PCB Handling:
It is recommend that cotton gloves are worn during repair work. This is to protect your
hands from chemical contamination and to protect the PCBs from fingerprints and
humidity.
SIM Card:
•Do not bend.
•Clean by using a soft dry cloth.

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Section 2
Unit Specifications
2

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PRODUCT FEATURE AND SPECIFICATION
Weight Approx. 112g
Volume Approx. 93cc
Form Factor Clamshell
Active flip Yes
LCD 120 x 160 TFT 65536(16bit) colours
2nd LCD 80 x 108 4096 colours
Antenna Build in
Navigation 4 way navigation key
Design
Camera 352Hx288V resolution
Type Li-ion
Voltage 3.7V (Max4.2V Min3.2V)
Capacity 780mAH (Min), 810mAh (Typ.)
Talk time Approx. 130 - 200 min *
Battery
Standby time Approx. 100 - 200 Hours *
Band GSM 900, DCS1800, DCS1900
GPRS Class 8
Voice codec FR, HR, EFR,
Multi-party Yes
Network
ALS Yes
Ring tones 23 pre-stored, 10 download
Ring tone format MIDI
Text input T9
Browser WML/xHTML/cHTML
Application
Phone book 500 + SIM
Harmony Ringer 40 PolyphonicMulti Media
Ring tone download Yes
* Battery life is Network dependent; variations may occur.
The N8800 HHP works closely with the network and the standby and talk times achieved
depend upon this. In particular the location of the HHP within the network, the type of
SIM, reception of area messages, the use of AMR, Full Rate speech, Half Rate speech or
Enhanced Full Rate speech and other factors will affect both standby and talk times.

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Transmitting Frequency
Range:
GSM : 890 - 915MHz
EGSM : 880 - 915MHz
DCS1800 : 1710 - 1785MHz
DCS1900 : 1850 - 1910MHz
Receiving Frequency Range:GSM : 935 - 960MHz
EGSM : 925 - 960MHz
DCS1800 : 1805 - 1880MHz
DCS1900 : 1930 - 1990MHz
TX - RX Duplex Spacing:GSM/EGSM : 45MHz
DCS1800 : 95MHz
DCS1900 : 80MHz
Channel Spacing:GSM/EGSM : 200KHz
DCS1800 : 200KHz
DCS1900 : 200KHz
Number of Channels:GSM : 124 (Numbered 1 to 124)
EGSM : 50 (Numbered 975 to 1023 & 0)
DCS1800 : 374 (Numbered 512 to 885)
DCS1900 : 299 (Numbered 512 to 810)
Power Class: GSM/EGSM : Class 4 (33 +/- 2dBm)
DCS1800 : Class 1 (30 +/- 2dBm)
DCS1900 : Class 1 (30 +/- 2dBm)
Data Rates (Packet): GSM/EGSM/DCS1800/DCS1900 :
Uplink : Up to 42.8Kbps (2 slot)
Downlink : Up to 85.6Kbps (4 slots)
Data Rates
(Circuit Switch):
GSM/EGSM/DCS1800/DCS1900 : Up to 14.4 Kbps

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TRANSMITTER (EGSM)
RF Power Output
Power Levels 15, decrementing in 2dB steps
Power Control Level 5 33dBm +/-2dB
Power Control Level 6 31dBm +/-3dB
Power Control Level 7 29dBm +/-3dB
Power Control Level 8 27dBm +/-3dB
Power Control Level 9 25dBm +/-3dB
Power Control Level 10 23dBm +/-3dB
Power Control Level 11 21dBm +/-3dB
Power Control Level 12 19dBm +/-3dB
Power Control Level 13 17dBm +/-3dB
Power Control Level 14 15dBm +/-3dB
Power Control Level 15 13dBm +/-3dB
Power Control Level 16 11dBm +/-5dB
Power Control Level 17 9dBm +/-5dB
Power Control Level 18 7dBm +/-5dB
Power Control Level 19 5dBm +/-5dB
TX Frequency Output
Low Channel (Ch 975) 880.2 MHz
Mid Channel (Ch 62) 902.4 MHz
High Channel (Ch 124) 914.8 MHz
TX Frequency Calculation (Ftx)MHz
(0 - 124)
(975 - 1023)
890 + (ARFCN x 0.2)MHz
890 + 0.2x(ARFCN - 1024)MHz
Phase and Frequency Error
Peak Phase Error < 20 degrees
RMS Phase Error < 5 degrees
Frequency Stability < +/- 90Hz

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TRANSMITTER (DCS1800)
RF Power Output
Power Levels 16, decrement in 2dB steps
Power Control Level 0 30dBm +/-2dB
Power Control Level 1 28dBm +/-3dB
Power Control Level 2 26dBm +/-3dB
Power Control Level 3 24dBm +/-3dB
Power Control Level 4 22dBm +/-3dB
Power Control Level 5 20dBm +/-3dB
Power Control Level 6 18dBm +/-3dB
Power Control Level 7 16dBm +/-3dB
Power Control Level 8 14dBm +/-3dB
Power Control Level 9 12dBm +/-4dB
Power Control Level 10 10dBm +/-4dB
Power Control Level 11 8dBm +/-4dB
Power Control Level 12 6dBm +/-4dB
Power Control Level 13 4dBm +/-4dB
Power Control Level 14 2dBm +/-5dB
Power Control Level 15 0dBm +/-5dB
TX Frequency Output
Low Channel (Ch 512) 1710.2 MHz
Mid Channel (Ch 699) 1747.6 MHz
High Channel (Ch 885) 1784.8 MHz
TX Frequency Calculation (Ftx)MHz 1710.2 + 0.2 x (ARFCN - 512) = Ftx MHz
Phase and Frequency Error
Peak Phase Error < 20 degrees
RMS Phase Error < 5 degrees
Frequency Stability < +/- 180Hz

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TRANSMITTER (DCS1900)
RF Power Output
Power Levels 16, decrement in 2dB steps
Power Control Level 0 30dBm +/-2dB
Power Control Level 1 28dBm +/-3dB
Power Control Level 2 26dBm +/-3dB
Power Control Level 3 24dBm +/-3dB
Power Control Level 4 22dBm +/-3dB
Power Control Level 5 20dBm +/-3dB
Power Control Level 6 18dBm +/-3dB
Power Control Level 7 16dBm +/-3dB
Power Control Level 8 14dBm +/-3dB
Power Control Level 9 12dBm +/-4dB
Power Control Level 10 10dBm +/-4dB
Power Control Level 11 8dBm +/-4dB
Power Control Level 12 6dBm +/-4dB
Power Control Level 13 4dBm +/-4dB
Power Control Level 14 2dBm +/-5dB
Power Control Level 15 0dBm +/-5dB
TX Frequency Output
Low Channel (Ch 512) 1850.2MHz
Mid Channel (Ch 657) 1879.2MHz
High Channel (Ch 810) 1909.8MHz
TX Frequency Calculation (Ftx)MHz 1850.2 + 0.2 x (ARFCN - 512) = Ftx MHz
Phase and Frequency Error
Peak Phase Error < 20 degrees
RMS Phase Error < 5 degrees
Frequency Stability < +/- 185Hz

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RECEIVER (EGSM)
RX Frequency Input
Low Channel (Ch 975) 925.2 MHz
Mid Channel (Ch 62) 947.4 MHz
High Channel (Ch 124) 959.8 MHz
RX Frequency Calculation (Frx)MHz
(0 - 124)
(975 - 1023)
935 + (ARFCN x 0.2)MHz
935 + 0.2x(ARFCN - 1024)MHz
BER (Bit Error Ratio) Type II BER <2.4% at -102dBm
Type II BER <0.1% at -15dBm

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RECEIVER (DCS1800)
RX Frequency Input
Low Channel (Ch 512) 1805.2 MHz
Mid Channel (Ch 699) 1842.6 MHz
High Channel (Ch 885) 1879.8 MHz
RX Frequency Calculation (Frx) Ftx + 95 Mhz = Frx MHz
BER (Bit Error Ratio) Type II BER <2.4% at -102dBm
Type II BER <0.1% at -23dBm

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RECEIVER (DCS1900)
RX Frequency Input
Low Channel (Ch 512) 1930.2MHz
Mid Channel (Ch 657) 1959.2MHz
High Channel (Ch 810) 1989.8 MHz
RX Frequency Calculation (Frx) Ftx + 80 Mhz = Frx MHz
BER (Bit Error Ratio) Type II BER <2.4% at -102dBm
Type II BER <0.1% at -23dBm

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Section 3
Introduction of
Service Level
Introduction of Service Level 1
Introduction of Service Level 2
3

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INTRODUCTION OF SERVICE LEVEL 1
The dealers at service level 1 will have to do the following:
1. Attend to the subscriber’s complaint. Receive the equipment for servicing from the
customer and checking that the warranty period is valid or not.
2. Check the external appearance of the main equipment, peripheral units, and accessories.
3. Check the normal operation and performance of the main equipment, peripheral unit,
and accessories.
4. If necessary, replace detachable parts, peripheral units, and accessories that cannot
be repaired. Keep a stock of good replacement phone and accessories.
5. If necessary, explain the correct method of operation to the customer.
6. Verify any faulty reported by the end-user at 2. and 3. Above.
7. Specify the symptom and fill out the fault report.
8. Send the fault report and faulty equipment to service level 2. Ask the subscriber to
wait for the equipment to be repaired.
9. In certain cases, replace the entire main equipment.
10.Receive back the repaired equipment and carry out a final check.
11.Return the repaired and correctly functioning equipment to the end-user.

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Receive the equipment for servicing
Is warranty period valid?
If not, charge the repair fee.
Physically inspect the equipment.
Check normal operation. Try to
verify the fault.
Fill out a fault report.
If necessary, replace
any detachable
peripheral parts or
accessories. Discard
consumable
accessories.
If necessary,
explain the
correct method
of operation to
the customer.
Fault
cleared?
Adequate stock of
good replacement
peripheral parts &
accessories
Send the fault report, faulty
main unit and / or repairable
accessories to Level 2.
Tell the customer to wait the
estimated maximum down time.
Is the case
urgent?
Wait to receive repaired
equipment from level 2.
Physical inspects the equipment.
Check normal operation.
Return the equipment to the
customer.
Replace the
entire main
unit and
accessories.
Adequate stock
of good
replacement
main units and
accessories.
Flow of Service Level 1
Go to Level 2
Return From Level 2
Y
es
No
Y
es
No

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TEST EQUIPMENT AND TOOLS FOR SERVICE LEVEL 1
No GSM tester and soldering are required for Service Level 1. The following
equipment and tools are recommended for this level.
1. Fully charged battery :
Use as a power source or a temporary replacement of original battery for faulty
equipment.
2. Workable SIM card :
Use to test the performance and functions of faulty equipment.
3. Rubber :
Use to clean electronic contacts, such as battery terminals, etc.
4. AC Adapter :
Use to test the charging function of faulty equipment and / or battery.
5. Simple Handsfree Kit.
Use to test the Handsfree relevant functions of faulty equipment.