Does The Phone Have A Reliable Connection To The Network (Gsm); Gsm Receiver Bit Error Rate (Ber) Ok; Does The Phone Give Realistic Rssi-Values; Hinku (N7500) Or Rap3G (D2800) Faulty - Nokia 6680 RM-36 Service Manual

Appendix A: RF Troubleshooting

5. DOES THE PHONE HAVE A RELIABLE CONNECTION TO THE NETWORK (GSM)?

This section refers to a situation when the phone registers to the GSM-network and is capable to make a call, but
the call is not reliable even if the GSM-network field strength is strong. The phone call is maybe disconnected or
interrupted.

5.1 GSM receiver Bit Error Rate (BER) ok?

• This test needs a GSM communication tester and if there is no that kind of tester available
continue troubleshooting in section 3.2
• Attach the phone to the product specific test jig and a GSM communication tester to the
RF-coupler. Coupler attenuation should be also taken into account during measurements. This
measurement should be done in an RF shielded box.
Close the shield box hatch.
•
• Make a GSM call against the tester
• Settings to the tester have to be done according to the 3GPP specifications:
Set base station downlink power to -102 dBm
-
• Bit Error Rate should be less than 2 %

5.1.1 Does the phone give realistic RSSI-values?

See section
•

5.1.2 Hinku (N7500) or RAP3G (D2800) faulty?

• RAP3G is not possible to replace

5.2 GSM transmitter power levels and transmit frequency ok?

• See section

5.3 GSM Transmitter phase error ok?

• See section

5.4 GSM (GMSK) modulation spectrum ok?

• See section
5.5 TX power vs. time ok?
• See section

6. DOES THE PHONE HAVE A RELIABLE CONNECTION TO THE NETWORK (WCDMA)?

This section means situation when the phone registers to the WCDMA-network and is capable to make a call, but the
call is not reliable even if WCDMA-network field strength is strong. The phone call is maybe disconnected or
interrupted.
3.2. "Does the phone give realistic RSSI-values?"
3.1. "GSM transmitter power levels and transmit frequency ok?"
3.3. "GSM Transmitter phase error ok?"
3.4. "GSM (GMSK) modulation spectrum ok?"
3.5. "TX power vs. time ok?"
Company Confidential
Copyright © 2005 Nokia. All rights reserved
"Does the phone give realistic
Nokia Customer Care
RSSI-values?".
A-113