NPM-6/6X
Company confidential
Troubleshooting Instructions
CCS Technical Documentation
Page 10
Copyright
Nokia. All rights reserved.
Issue 2 06/03
Figure 4: HELGA IC troubleshooting
HELGA
troubleshooting
Baseband
troubleshooting
Synthesizer
troubleshooting
Check with oscilloscope:
-TXI/TXQ signals
--VR1, VR2, VR4, VR5, VR6 = 2.8V
-VrefRF01 = 1.35 V
-HELGA serial interface
-TXP & TXC signals
OK ?
No
Check with RF probe:
-4G VCO out signal
- 3589.6 MHz (GSM900)
-3495.6 MHz (GSM1800)
- 3760 MHz (GSM1900)
Level >-10dBm (*
OK ?
No
dead
Replace HELGA
Yes
Check modulator
output components
OK ?
Replace
faulty
component(s)
*(When 1kOhm passive probe is used,
correct the measurement result by +26dB
Check with RF probe:
-4GVCO out signal
-3589.6MHz (EGSM900)
-3495.6 MHz (GSM1800)
-3760 MHz (GSM1900)
Level >-10dBm