User Guide

Nokia Customer Care RF Description and Troubleshooting

6255/6255i/6256/6256i (RM-19)

Table 12 includes the measure logic levels for the N7160.

If the logic levels are significantly off (+/- 0.2V), replace the N7160 and re-measure. If

the voltages are still out of specifications, refer to the Baseband Troubleshooting chapter.

N7160 Receiver Overview

Keep the following points in mind regarding the N7160 receiver:

• There is a separate LNA for 800MHz (Cell and AMPS) and 1900MHz (PCS).

• There is a separate RFA (inside N7160) for 800MHz (Cell and AMPS) and

1900MHz (PCS).

• After the RFA, there is a mixer, and then the signals are separated by CDMA (Cell

and PCS) and AMPS.

For example, if there is no IF frequency (128.1MHz) check both Cell and PCS. If

only one has 128.1MHz at L753, ensure that IF_SEL is working. If it is, then

replace the N750 due to a bad RFA.

If Cell and AMPS are working but PCS is not, look at the band select line and the

PCS LNA before replacing the N7160.

Table 12: Rx Front-end (N7160) Logic Levels

Mode

Logic Input Voltages

IF_SEL BAND GAIN_CTL

AMPS High Gain 2.8 V 0.1 V 2.8 V

AMPS Low Gain 2.8 V 0.1 V 0 V

Cell CDMA High Gain 0 V 0.1 V 2.8 V

Cell CDMA Low Gain 0 V 0.1 V 0 V

PCS CDMA High Gain 0 V 2.7 V 2.8 V

PCS CDMA Low Gain 0 V 2.7 V 0 V