Nokia 6267 RM-210 Service Manual

Nokia 6267 RM-210 Service Manual Manual pdf 92 page image

General RF troubleshootingIntroduction to RF troubleshootingMost RF semiconductors are static discharge sensitiveESD protection must be applied during repair (ground straps and ESD soldering irons).Pre-bakingThese parts are moisture sensitive and must be pre-baked prior to soldering:• RFIC N7505• Front End Module (FEM) N7520Discrete componentsIn addition to the key-components, there are a number of discrete components (resistors, inductors andcapacitors) for which troubleshooting is done mainly byvisual inspection.Capacitors: check for short circuits.Resistors: check value with an ohm meter.Note: In-circuit measurements should be evaluated carefullyMeasuring equipmentAll 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 & SchwarzCMU200. (Alternatively a spectrum analyser and an RF generator can be used. Some tests in this guide arenot possible to perform if this solution is chosen).Note: A mobile phone WCDMA transmitter should never be tested with full TX power (only it possibleto perform the measurements in a good RF-shielded room). Even low power WCDMA transmittersmay disturb nearby WCDMA networks and cause problems to 3G cellular phone communication ina wide area.Note: All measurements with an RF coupler should be performed in an RF-shielded environmentbecause nearby base stations can disturb sensitive receiver measurements. If there is no possibilityto use RF shielded environment, testing at frequencies of nearby base stations should be avoided.Level of repairThe scope of this guideline is to enable repairs at key-component level. Some key-components are notaccessible, i.e. not replaceable. Please refer to the list ofNon replaceable RF components.Note: If the RF shieldning can is removed (for measurement or repair), it must always be replacedwith a new one.RM-210RF troubleshootingPage 4 –6 COMPANY CONFIDENTIAL Issue 1Copyright © 2007 Nokia. All rights reserved.