General RF troubleshooting
Introduction to RF troubleshooting
Most RF semiconductors are static discharge sensitive
ESD protection must be applied during repair (ground straps and ESD soldering irons).
Measuring equipment
All measurements should be done using:
•
An oscilloscope for low frequency and DC measurements. Recommended probe: 10:1, 10Mohm//8pF.
•
A radio communication tester including RF generator and spectrum analyser, for example Rohde & Schwarz
CMU200. (Alternatively a spectrum analyser and an RF generator can be used. Some tests in this guide are
not possible to perform if this solution is chosen).
Note: A mobile phone WCDMA transmitter should never be tested with full TX power (it is only
possible to perform the measurements in a good RF-shielded room). Even low power WCDMA
transmitters may disturb nearby WCDMA networks and cause problems to 3G cellular phone
communication in a wide area.
Note: All communication Test Set Screen dumps are from CMU200. Other testers are different.
Note: All measurements with an RF coupler should be performed in an RF-shielded environment
because nearby base stations can disturb sensitive receiver measurements. If there is no possibility
to use RF shielded environment, testing at frequencies of nearby base stations should be avoided.
Level of repair
The scope of this guideline is to verify functionality of the cellular RF block without removing RF shield.
RM-484; RM-485; RM-486
RF Troubleshooting
Issue 1 COMPANY CONFIDENTIAL Page 4 –5
Copyright © 2009 Nokia. All rights reserved.
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