Tx Rf Probe Points; Dc Test Points; Receiver Rf Troubleshooting - Nokia 6275 Rf Description And Troubleshooting

6275/6275i (RM-154)
RF Description and Troubleshooting

Tx RF Probe Points

Figure 14 shows the Tx RF probe points of the PWB.
PCS Frequency 1880 MHz
PCS TX IC out: PCS PA in:
-7 dBm -13 dBm
Cell TX IC out: -7 dBm Cell PA in: -7 dBm
Amps -33 dBm
Cell, Amps Frequency 836.25 MHz

DC Test Points

Figure 15 shows the DC test points.
Vbatt 3.2 to 4.7 V
VR1B: 4.75 V (TX)
VR1A: 4.75 V (Synth)
VR2: 2.78 V (TX)
VR4: 2.78 V (RX)
VR7: 2.78 V (RX)
VR3: 2.78 V (Synth)

Receiver RF Troubleshooting

The heart of the receiver is the Rx Front-end IC, which contains two LNAs and mixers.
The other components are passive. There are two RF SAW filters for the Cell and PCS
bands. In addition, there are two IF filters, an IF SAW for CDMA and an IF Crystal for
AMPS.
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PCS PA out:
+17 dBm
Cell PA out: +20 dBm
Amps -33 dBm
Amps -6 dBm
Figure 14: Tx RF probe points
VR6: Rx 2.78 V (TX)
Figure 15: DC Test Points
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Diplexer out:
PCS +16 dBm
Cell +10 dBm
PCS Duplexer
Amps +1 dBm
out: +15 dBm
Cell Duplexer out:
+20 dBm
Amps -7 dBm
VR5: Rx 2.78 V (RX)
Issue 1 - September 2006
PCS PDM:
PA_DC_DC = 110
PA_Bias = 85
AGC1 = -130
Amps PDM:
PA_DC_DC = 197
PA_Bias = 129
AGC1 = -512
Pwr Detector in
PCS: -13 dBm
Cell: +4 dBm
Amps: -20 dBm
Cell PDM:
PA_DC_DC = 110
PA_Bias = 85
AGC1 = -130
VIO 1.8 V