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PAMS Technical Documentation
Troubleshooting
In the PCS band the RX_GS input to the up–converter N01 is NOT used. Instead the
external LNA is switched on and off with Penta N303 Pin 9 (output P5) (TP116). Check
that the external LNA is being switched on and off by probing. If this is the case then
there is probably a fault with the external LNA. Check the transistor V705 and its collec-
tor components L710. Also check the bias circuitry V704 and L708.
NOTE: If any of these components are damaged and are replaced, then the Rx IF AGC
must be retuned.
1900 CDMA Tuning Rx IF AGC
Description of Test
The RIF and TIF AGC is approximately a second order curve. This curve is split into 16 seg-
ments for both Transmitter and Receiver. Offset and slope values are stored in eeprom for
each of these 16 segments. The offset for the segments are computed from the 3–point
calibration performed in this test, then a 2
and Slope computed. This tuning is done by putting signal level 1 into the receiver, the
RX_IF_AGC will then automatically adjust for max CAFÉ input and the RX_IF_AGC is
noted. This process is then repeated for signal levels 2 and 3.
Definition of Result
The results of the three point tuning are the 16 slope and offset values which are stored
to eeprom RF_TUNE_PCS_RX_AGC_OFF-SET_ SLOPE_HANDLE.
Issue 1 04/01
Disassembly/Troubleshooting Instructions
order approximation is made and the Offset
nd
Nokia Mobile Phones Ltd.
NSD-6
Page 41
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Table of Contents
Troubleshooting
