Rf Description And Troubleshooting - Nokia RH-6 Series Rf Description & Troubleshooting

CCS Technical Documentation

RF Description and Troubleshooting

The sections below provide instructions how to check, repair and calibrate the RF section
of RH-6 phones.
It is assumed that for tuning and repair the phones are disassembled and tested within a
repair jig MJ-7.
The following types of measurements can be done for diagnosis and repair of RH-6
phone modules:
• RF measurements are done using a Spectrum Analyzer together with a high-fre-
quency probe. (Note, that signal will be significantly attenuated). Correct attenu-
ation can be checked using a "good" phone board, for example.
• LF (Low frequency) and DC measurements are done with a an oscilloscope
together with an 10:1 probe.
• For receiver measurements, a signal generator with frequencies up to 2000 MHz
is required. Most of the radio communication testers like CMD55 or CMU200 can
be used as signal generator. The signal generator is connected to the antenna
port using the repair jig MJ-7.
• Output level measurements of the transmitter are done with a power meter,
which is connected to the antenna port using the repair jig MJ-7.
Always make sure that the measurement set-up is calibrated when measuring RF param-
eters at the antenna port. Remember to include the correct losses of the module repair
jig (as stated on MJ-7) and the connecting cable when realigning the phone.
Most RF semiconductors are static discharge sensitive. ESD protection must be used dur-
ing repair (wrist straps and ESD proof soldering irons).
Mjoelner RF ASIC is moisture sensitive. Therefore, Mjoelner RF ASIC must be in appropri-
ate condition or pre-baked prior to soldering.
RX calibration done via Phoenix software is temperature sensitive because of calibration
of the 26 MHz reference oscillator (VCXO). According to Mjoelner specification, ambient
temperature has to be in a range from 22°C to 36°C.
Apart from key-components described in the following sections there are a lot of dis-
crete components (resistors, inductors and capacitors) for which troubleshooting is done
by checking if soldering of the component is done properly and checking if the compo-
nent is missing from PWB. Capacitors can be checked for short-circuiting and resistors
for value by means of an ohm-meter, but be aware: in-circuit measurement results have
to be evaluated carefully.
Issue 1 10/2003
Company Confidential
Copyright © 2003 Nokia Corporation.
Company Confidential
7 - RF Description & Troubleshooting
RH-6
Page 3