Nokia 2170 Service Manual trouble

Programme’s After Market Services

NHP–4 Series Transceivers

Disassembly &

Troubleshooting

Issue 1 04/99

NHP–4

PAMS

Disassembly & Troubleshooting

Technical Documentation

CONTENTS

Disassembly Instructions 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HD891 Baseband Troubleshooting 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overview of baseband troubleshooting 8. . . . . . . . . . . . . . . . . . . . . . . . . . .

General 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Failures 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Other Possible Failures 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Specific Sections 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reset Logic 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Clocks 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Watchdog 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Charging Circuit 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MCU 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DSP 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CODEC & Differential Amplifier 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Failures 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Current consumption failures 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Phone takes all available current 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Phone does not take current at all 13. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Current consumption OK during power–up, then fail 13. . . . . . . . . . . .

Troubleshooting Diagram; Flash Programming OK, part 1 14. . . . . . . . . .

Troubleshooting Diagram; Flash Programming OK, part 2 15. . . . . . . . . .

Troubleshooting Diagram; Flash Programming OK, part 3 16. . . . . . . . . .

Troubleshooting Diagram; Flash Programming OK, part 4 17. . . . . . . . . .

Troubleshooting Diagram; PWR Button Fault 18. . . . . . . . . . . . . . . . . . . . .

Troubleshooting Diagram; Audio Fault 19. . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Up Sequence Diagram 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repairing Instructions for Flash Faulty Units 21. . . . . . . . . . . . . . . . . . . . . .

Calibrate Battery Voltage (VBATDET)= 6.0V 22. . . . . . . . . . . . . . . . . . .

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Calibrate Charge Voltage (VC)= 6.0V 22. . . . . . . . . . . . . . . . . . . . . . . . .

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Troubleshooting Diagram; Power Up and MCU Self tests Malfunctions 23

Power Up Malfunction 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Diagram; Power Up Malfunction 29. . . . . . . . . . . . . . . . . .

Important Information 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.8304MHz clock 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Disassembly & Troubleshooting

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Disassembly Instructions

Disassembly & Troubleshooting

Remove the battery.

Now remove two back

cover screws and re­move the back cover
by lifting it away.

2

1

4

3

6

Then remove six

chassis screws.

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Technical Documentation

Remove the chassis by lifting.

Turn around the chassis and open

the display module a little.
Open the display module connector

by pressing both sides of connector
and slide off the display module
cable.

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Turn chassis again and remove

four chassis screws.

Disassembly & Troubleshooting

1

4

3

2

Remove the plastic shield and

throw it away (it is disposable).
Now you can separate the sys-

tem module from the bottom
shield by lifting it away.

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Disassembly & Troubleshooting

HD891 Baseband Troubleshooting

Overview of baseband troubleshooting

Baseband oriented failures are typically discovered during flash and

alignment. Before programming the flash memory, the phone is started in

minimum mode and current consumption is measured. If current

consumption is within acceptable limits and the MCU software version is

successfully read via MBUS, the flash is then programmed. If flash

programming fails, the phone is taken off line where MCU self tests will be

performed at a separate troubleshooting station. During MCU self tests,

address and data lines to the major components of the baseband are

tested. Each test returns the number of the test and the results ( OK /

failed ). Test information is also stored to a phone test file, which can be

available for later use.

If the phone can be flashed and the DSP downloaded, the baseband is

generally functioning properly. If not, referring to the test file of the phone

will aid in the detection of defective components or connections.

Technical Documentation

General

In case of current consumption/MBUS registration failure, more specific

measurements of voltages, clocking signals and states of reset signals

must be evaluated.

The purpose of this document is to define a method by which failures in

the baseband of the phone can be detected and corrected. Each section

of the circuit shall be described in adequate detail such that the reader

may be able to verify whether each section is functioning properly, and if

not, where the problem resides.

Required servicing equipment:

1Service software
1Power supply (1.0 A)
1Digital multimeter
1Oscilloscope
1Modular cable
1RS232/MBUS adapter
1Soldering iron and related tools.

General Failures

The most common baseband failures detected in production will likely be

the following:

1) The phone will not flash (phone seems dead).

2) The DSP will not download.

3) Phone will power up in minimum mode and then power down.

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Other Possible Failures

Less likely failures may be:

1) Power circuit

2) Reset logic

3) Clocks

4) Charging circuit

5) BTEMP

6) BTYPE

7) Power to differential audio circuit and headset (VAHS)

8) RFTEMP

9) Watchdog circuit

Troubleshooting Specific Sections

Below describes in detail each of the main circuit sections. Circuit

verification and troubleshooting can be performed by verifying the signals

and voltages described in each section.

Disassembly & Troubleshooting

Power

3 Volt Switching Power Supply

The MAX887 (N704) is the 3V power supply for the baseband. Pin 8

should have battery power at all times (unless, of course, the battery is not

installed), and pin 7 is the output which is approximately 3.15V. This

output by nature will be very noisy. However, it is filtered by an LC circuit

and a rectifying diode which gives a fairly clean supply. This should be

evident by probing the signal labeled 3VD.

Pin 1 is the control pin for the power supply. The supply is active when

this pin is at a logic high (in this case 2.5V), and powers down when it is at

a logic low. It is connected directly to the watchdog circuit, which controls

whether the power supply is on or off.

Pin 6 is the sync pin, which allows the supply to switch in sync with the

clock driving it. The clock frequency should be 307kHz, but should still

function with no clock at all.

3V Power Distribution

Check the MCU (D706) supply voltage 3VD (3.15V) on pins 5 and 42, and

VREF (3.15V) pin 60. Check voltages of MCU related memory

components: FLASH (D702) pins 30, 31 and 11; RAM (D708) pin 7; and

EEPROM (D703) pin 8.

Check the ASIC (D705) supply voltage 3VD (3.15V) on pins 13, 22, 27,

44, 60, 65, 74, 88,103, 109, 117, 132, 146, 151, 161, and 176.

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Disassembly & Troubleshooting

Check the,DSP (D707) supply voltage 3VD (3.15V) on pins 8, 11, 36, 39,

49, 64, 76, 87 and 90. 3VD (3.15V) is also fed to the DSP RAM (D709) to

pin 11 and 33.

Check the CDRFI (N703) supply voltage 3VD (3.15V) on pins 32, 33, 60,

62, 2, 6, 8 and 19.

Check the supply voltages of the audio CODEC (N706). 3VA (3.15V) is

fed to pins 41 and 42. 3VD (3.15V) is connected to pin 18.

4.8 Volt Linear Regulator

The 4.8 volt linear regulator (N707) supplies power the the flex circuit

board (UIF), the differential audio circuit at the output of the CODEC and

leading to the bottom connector, and the headset accessory.

Pin 6 is the power input to the regulator and should be connected to

battery voltage. Pin 1 is an on/off switch. When this pin is high the

regulator is on, and when low it is off. The output is at pin 4 and is labeled

5VD.

Technical Documentation

Reset Logic

XPWR_RESET is the main reset for the entire baseband. It is generated

at pin 7 of N705 and is associated with a RC delay at pins 1 and 5 to give

the circuit time to power up before letting the reset go inactive. With the

battery installed, pins 2 and 6 of N705 must always be at 2.5 volts (these

pins are connected to the 2.5 volt reference diode).

XPWR_RESET drives only the CDSB ASIC at pin 2. When the ASIC is

fully active it then drives the reset (XSYS_RESET, pin 168) to the MCU

(pin 10) and the DSP (pin 69). This reset is asserted whenever the

battery is plugged in, or when the power–on button is pressed. All resets

are active low. When the phone is up and running, all resets should be

high.

Clocks

The MCU (D700), DSP(D707), and ASIC(D705) must all have an active

clock driving them in order to function. The clocks are fundamentally

derived from the VCTCXO (G100) in the RF section. It emits a 15.36MHz

sinusoid which drives the CDRFI (N703, pin 1). The same RF section

also emits a 9.83MHz sinusoid which drives the CDRFI at pin 3. These

signals MUST be present in order for the phone to function.

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The CDRFI then generates the squarewave version of these two

sinusoids and sends them to the ASIC (15.36MHz at pin147 and 9.83MHz

at pin162).

Pin 104 of the ASIC drives the MCU clock (MCU_CLK) at MCU pin 69,

and drives the DSP clock (DSP_CLK) at DSP pin 68.

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