Is Rap3G Asic Getting Ok Vrefcm-Signal From Hinku (N7500)? Signal Level Ok - Nokia RM-42 Service Manual

Appendix A: RF Troubleshooting
3.2.2.11.1.2 Replace Retu
3.2.2.11.1.3 Replace Hinku (N7500) or Vinku (N7501) or VCTCXO (G7501) or all three components
3.2.2.11.2 BB AFC-voltage ok?
• Measurement can be done with an oscilloscope and a probe
• Connect the probe to R7509 (or C7533)
• AFC-voltage may vary between 0.1 - 2.3 V. Typical value is 1.2 V. Phoenix "RF Controls" tool can be
used to change the AFC value. Voltage level should be about 0.1 V with AFC value -1024 and about
2.3 V with AFC value 1023.
3.2.2.11.2.1 Low pass filter components R7509 and C7533 ok?
Check that components are in place and solder joints are ok
•
• Disconnect the power supply from the phone and check R7509 resistance value with an
ohmmeter.
• Use an ohmmeter to find out also if the AFC-line is short-circuited to the ground. If short-circuit is
found replace C7533. If this does not help then go to the next steps.
3.2.2.11.2.2 VCTCXO ok?
• Remove R7509. If AFC-voltage is correct after removing then replace faulty VCTCXO G7501 and
solder R7509 (new component) back to the PWB
3.2.2.11.2.3 Replace Retu
3.2.2.11.3 Replace VCTCXO G7501
3.2.2.12 Replace Hinku ASIC (N7500)

3.2.3 Is RAP3G ASIC getting ok VREFCM-signal from Hinku (N7500)? Signal level ok?

• GSM receiver has to be active before VREFCM signal can be measured. Procedure is explained in
section "GSM RX chain activation for manual measurements".
• Measurement can be done with an oscilloscope and a probe.
• Connect the probe to J7516.
VREFCM voltage should be about 780 mV (continuous voltage).
•
3.2.3.1 Hinku (N7500) RB_EXT voltage ok?
• GSM receiver has to be active before Hinku's RB_EXT voltage can be measured. Procedure is
explained in section "GSM RX chain activation for manual measurements".
• Measurement can be done with an oscilloscope and a probe.
• Connect the probe to R7504.
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