User Guide

Nokia Customer Care 6(b) - RF Troubleshooting Instructions
RH-37
Issue 1 07/04 Nokia Corporation Page 5
General Information on RF Troubleshooting
Notes:
Several bills of material (BOM): There are two different kinds of VCOs, VCTXOs, RF-PAs, SAW-fil-
ters and Antenna Switches (ASM) assembled. They may only be replaced with the same type as the
original component (from the same manufacturer).
Phoenix version: In this document there are example measurements being depicted with pictures of
AMS-Phoenix, version A 2004.06.1.69. In later versions pictures of menus and windows may look dif-
ferently.
Layout version: The drawings of test points and component placement in this version of the document
are taken from build B4.0 layout (1cna_41). If you use the document for newer layout versions, make
sure to use the corresponding assembly and test point drawings.
Test environment
It is assumed, that the phones are disassembled and tested with a repair jig MJ-22R.
The following measurements have to be done for repairing the phone boards:
• RF measurements shall be done using a spectrum analyzer together with a high-
frequency probe. Note that the signal will be significantly attenuated. Correct
attenuation can be checked using a “good” phone board for example.
• LF (low frequency) and DC measurements shall be carried out with an oscillo-
scope together with a 10:1 probe.
•For receiver measurements, a signal generator specified for frequencies up to
2000 MHz is required. The signal generator is connected to the antenna port of
the repair jig.
Most of the radio communication testers, like CMU200, can be used as a signal
generator, but make sure to have a continuous (CW) signal without modulation
for alignment purposes.
• Transmitter output level measurements shall be done with a power meter
which is connected to the antenna port of the repair jig.
Always make sure that the measurement set-up is calibrated when measuring RF param-
eters at the antenna port. Remember to put the correct losses of the module repair jig
and the connecting cable in Phoenix or in the set-up programs of the RF generators
when realigning the phone.
Apart from key-components described in this document, there are a lot of discrete com-
ponents (resistors, inductors and capacitors) for which troubleshooting has to be done by
checking its proper soldering and complete assembly on the PWB. Capacitors and resis-
tors can be checked by means of an ohm-meter, but be aware in-circuit measurements
should be evaluated carefully.