Introduction To Rf Troubleshooting; Non Re-Workable Rf Components; Maintenance Overview - Nokia RM-761 Service Manual

RM-761; RM-799; RM-800
RF Troubleshooting

Introduction to RF Troubleshooting

For the RF troubleshooting, generally 2 types of measurements are used: RF measurements and LF
measurements.
RF measurements are done with a spectrum analyzer (or spectrum analyzer alike?) and a high-frequency
probe, e.g. Agilent E4440A. Note that the test jig has some losses, which must be taken into consideration
when calibrating the test system.
LF (low frequency) and DC measurements should be done with a 10:1 probe and an oscilloscope. The probe
used in the following is a 10mW/10pF probe. For the other types of probes the voltages displayed may be
slightly different. Always make sure the measurement setup is calibrated when measuring RF parameters on
the antenna pad. When re-aligning the phone, the loss in the module repair jig should be included.
Most RF semiconductors are static discharge sensitive, i.e. ESD protection must be added during repair
(ground straps and ESD soldering irons). The FEM and the X-GOLD213 are also sensitive to moisture, i.e. these
parts must be pre-baked prior to soldering.
Key components are described in this document but there are also a lot of discrete components (resistors,
inductors and capacitors) where the troubleshooting is done by checking if soldering of the component is
done properly and checking if the component is missing from PWB. Capacitors can be checked for short-
circuiting and resistors for value by means of an Ohm meter. However it should be noted that in-circuit
measurements should be evaluated carefully.

Non re-workable RF Components

The non-reworkable components for the Quantum are the X-GOLD213 (D3100) and the combo memory
(D3000). All other components are reworkable.

Maintenance Overview

When the phone is received at the service centre, it is fully assembled, and it is the objective to identify the
failure area in the phone by doing fast troubleshooting and then locate the failed component(s). Since the
X-Gold213 IC and the combo memory are non-replacebale components, it should be the primary task to
identify whether the failure is related to these components or not. In case of failure of the X-GOLD213 or the
Issue 1
Figure 35 D3100 and D3000 are the non- reworkable components
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