Receiver Troubleshooting; General Instructions For Rx Troubleshooting; Path Of The Received Signal; Fault Finding Charts For Receiver Chain - Nokia NPC-1 Series Troubleshooting Instructions

NPC-1
Troubleshooting Instructions

Receiver Troubleshooting

General instructions for RX troubleshooting

Start the Phoenix-software and use it to start the required RX-mode of the mobile
phone. The troubleshooting flowchart is divided into three steps: (1) general checking,
(29 local checking and (3) RX- chain checking.
Always use an RF-cable connected from an external RF-connector to the analyzer via
(RF-power) attennuator. This is important to protect the analyzer against excessive RF-
power and not to allow leakage of undesired RF-power into the cellular frequencies.
1 Start the Phoenix-software and select the TX mode under Testing (AMPS,
DAMPS).
2 It is useful to select the mid channel (383 for AMPS/DAMPS) and the power level
2.
Note: Before changing ASICS or Filters, all solderings and missing components must
be checked visually. After any possible component changes, the phone must be tuned
with the Phoenix autotune SW .

Path of the received signal

Block level description of the receiver:
(Antenna/ext RF) – Diplexer – Duplexer – Low Noise Amplifier (LNA) – RX band filter –
First mixer – 135.54 MHz RX IF filter – IF-amplifier – second mixer – 14 kHz low-pass fil-
ter – adjustable IQ amplifier – Baseband.

Fault finding charts for receiver chain

AMPS
Page 22 ãNokia Corporation
PAMS Technical Documentation
Issue 1 10/01