NSD–1
Disassembly / Troubleshooting Instructions
PAMS Technical Documentation
Page 35
Issue 2 09/00
Nokia Mobile Phones Ltd.
read from the phone. The LNA is switched from High Gain mode to Low
Gain Mode. The RX_IF_AGC is allowed to readjust itself to again make
the best use of the CAFÉ ADC and the RX_IF_AGC is read a second
time. The result is the Gain delta between High Gain and Low Gain
modes.
Definition of Result
The displayed result is the High Gain – Low Gain delta in dB after apply-
ing the PDM difference to the previously computed 3–point curve fit. This
delta should be between 21 and 30dB. It is stored to eeprom handle
RF_TUNE_RX_GS_HANDLE.
Manual Verification
Use WinTesla as follows:
Trouble Shooting
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 it’s collector 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.