Nokia 252 Disassembly Troubleshooting

Programmes After Market Services

NHA–3 Series Transceivers

Disassembly &
Troubleshooting

Issue 2 06/98

NHA–3

PAMS

Disassembly & Troubleshooting

Technical Documentation

Contents

Disassembly Instructions 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TroubleShooting Section 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Setup 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Chart 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Receiver Fault 1 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Receiver Fault 2 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Transmitter Fault 1 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Transmitter Fault 2 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Call Set–up Fault 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Logic Fault 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Earphone Level/Modulation Level Fault 14. . . . . . . . . . . . . . . . . . . . . . .

Display or Keypad Fault 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Call Set–up Fault 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page 2

Issue 2 06/98

PAMS

NHA–3

Technical Documentation

Disassembly Instructions

1. Antenna

Rotate anti–clockwise approximately 90 degrees and remove from top of
phone.

2. A Cover

A. Remove the battery pack (not shown).
B. Remove the four silver Torx screws. (2B)
C. Lift the A cover from the bottom end and it will come off.
D. The keymat is now loose.

3. Microphone

The microphone will now pull out of the system connector.
( Contact is made by two springs.)

4. PCB’s

Disassembly & Troubleshooting

A. Remove the three black Torx screws. (4A)
B. The UI and Engine PCB’s will lift out of the B cover. The PCB’s are held
together by a 44 way connector and can be pulled apart.

5. Engine PCB

The lids of the RF screens are removeable, however, once a lid has been
removed we recommended that you either solder it back to the frame of
the shield or replace it.

6. UI PCB

A. The metal speaker retainer is clipped to the PCB in six positions and
can be removed by easing it from the PCB.

B. The rubber gasket and the speaker are now free to be removed.

Issue 2 06/98

Page 3

NHA–3

PAMS

Disassembly & Troubleshooting

4A

6A

6B

Technical Documentation

2C

2D

3

4A

4A

4B

1

2B

2B

Page 4

2B

2B

Issue 2 06/98

PAMS

NHA–3

Technical Documentation

Troubleshooting Section

The purpose is to define fault block of the module and then find out the
broken component. The trouble shooting diagram has been planned so
that the fault, whatever it is, can be found by as simple measurements as
possible.

The flow diagrams give you the overview of the blocks. The purpose is
that you proceed through the flow diagram so that, if your answer is YES
for the asked question, go straight to the next level, but if your answer is
NO, you have to go the subbranch.

Required servicing equipment:

– NHA–3 Wintesla Service Software (product code: 8400597)
– Variable Power Supply Unit
– Digital multimeter
– Oscilloscope

Disassembly & Troubleshooting

– H700 Service Accessories
– MJS–2 Test Frame (NMP Part Number 0775095)
– RS232/MBUS adapter
– CMT/Marconi
– RF Spectrum Analyser
– Spectrum Analyser Probe HP85024A (300Khz to 3Ghz, attenuation

10:1)

Equipment Setup

In order for the faultfinding sections to be accurate, the servicing
equipment that is being used must be set to an identical state to when the
measurements were initially carried out. This section contains the settings
for the relevant faultfinding sections.

Issue 2 06/98

Page 5