Схема сотового телефона Other ERICSSON GH 688/GA 628

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GH688,GA628, Standard Electrical Repairs
4/00021-2/FEA 209 544/1.G
1 Conditions
1.1 Component classes.
All the components in the phone are divided into classes and after every componentin the troubleshooting guide you have a class written. The components are dividedinto four classes: A, B, C and D.The class of the component depends on how muchof the phone's performance is affected when replacing it.
Class A and B:A test call towards the "real" net (not only towards a GSM test
instrument) and run it through the normal tests is enough to verify thefunctionality since the performance of the phone is only slightlyaffected.
Since the tolerances of the component are so great it can substantiallyaffect the performance of the phone you need to calibrate it at stationlevel after replacing the component.
Class D components need to be calibrated at board level using veryadvanced equipment and may therefore not be replaced.