User Guide

Nokia Customer Care RF Description and Troubleshooting

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

Tx UHF LO (N7000) Troubleshooting

There are two fixed LOs, 3296.16~3395.88MHz for cell band and 3700~3819.90MHz for

PCS band. This is the only LO for up-conversion. Be sure to monitor the control voltage at

R7001. When the N7000 LO is locked, this control voltage should be between 1.2 and

1.8Vdc.

Figure 51: Tx UHF LO layout and test points

Table 18 shows the description for each component in Figure 51.

Table 18: Tx UHF Test Point Values

Test

Point

Description Value

1 Lock voltage DC between 1.2 and 1.8V

2 N7000: Measure voltage by probing

the top of the chip.

Cell channel 384: 3346.08MHz, -55 to -65dBm

PCS channel 600: 3760MHz, -54 to -65dBm

3VIO 1.8V

4 Vcc_Vco 2.3V

5VR6 2.8V

1 3

Cell PA

PCS PA