User Guide

Nokia Customer Care

Appendix A: RF Troubleshooting

A-84

Company Confidential

explained in section “Transmitter troubleshooting”.

• Measurements can be done with a spectrum analyser and an RF probe. Spectrum analyser RBW =

VBW = 10 MHz, Span ≤ 2 MHz, sweep time 100 ms. Spectrum analyser centre frequency should be

set according the used TX channel (see section “Frequency mappings”).

• Connect the RF probe to R7520. The RF-level should be about the same on both ends of the

resistor. Check output level with 0 dBm (“0”) power level.

- Power level (“0”) – Output level should be about -45…-48 dBm

• Check if output levels of Vinku are as expected.

4.1.2.1.1 RF operating voltage VBAT_ASIC ok?

• See section

“RF operating voltage VBAT_ASIC ok?”

4.1.2.1.2 Vinku (N7501) regulator voltages VREG1, VREG2 ok?

• WCDMA transmitter has to be active before VREG1 and VREG2 voltages can be measured. Procedure

is explained in section “Transmitter troubleshooting”. Measurements can be done with an

oscilloscope and a probe.

• VREG1: Connect the probe to C7543

• VREG2: Connect the probe to C7548 (or C7547)

• VREG1 and VREG2 voltage levels should be 2.65 – 2.86 V. Typical value is 2.7 V.

4.1.2.1.2.1 Vinku (N7501) RB_EXT voltage ok?

• WCDMA transmitter has to be active before Vinku’s RB_EXT voltage can be measured. Procedure is

explained in section “Transmitter troubleshooting”.

• Measurement can be done with an oscilloscope and a probe.

• Connect the probe to R7521.

• RB_EXT voltage should be 1.325 – 1.375 V.

4.1.2.1.2.1.1 VREFRF01-voltage ok?

• Measurement can be done with an oscilloscope and a probe.

• Connect the probe to R7503.

• VREFRF01 voltage should be 1.325 – 1.375 V. Typical value is 1.35 V.

4.1.2.1.2.1.1.1 Desolder R7503. Is VREFRF01 voltage still wrong?

• Remember to solder a new component to R7503 pads after measurement.

4.1.2.1.2.1.1.1.1 Capacitors C7518, C7520 and C7570 working correctly?