Nokia RH-30 Series Troubleshooting Instructions page 15

TX EDGE Troubleshooting
ICQ: 343183001 QQ: 35070846 Email: Serviceic@yahoo.com.cn
Check output signal level:
+24...+30dBm@836.6MHz(GSM850)
+24...+30dBm@897.4MHz(GSM900)
+22...+29dBm@1747.8 and 1880MHz
+24...30dBm@897.4MHz(GSM900)
(GSM1800&1900)
+22...+29dBm@1747.8and 1880MHz
OK?
OK?
(GSM1800/1900)
No
TX signal found?
Yes
Check with RF probe signal level on
PA input:
(GSM850 & 900)
~-8dBm@PCL=8 (GSM900)
~-10dBm@PCL=2 (GSM1800&1900)
OK?
Yes
Start TX Edge power level tuning and check tuned DAC values:
Highest level ~700...800(GSM900); ~630...730(GSM1800&1900)
Highest level~700...800(GSM850&900);~630...730(GSM1800&1900)
Yes
Lowest level ~340...410(GSM900); ~250...360(GSM1800&1900)
Lowest level~340...410(GSM850&900);~250...360(GSM1800&1900)
Base level ~190...260(GSM900); ~150...250(GSM1800&1900)
Base level~190...260(GSM850&900);~150...250(GSM1800&1900)
Major differences?
No
Check control voltages with
oscilloscope:
(GSM850/900)
Pa Iref ~2V peak (GSM900)
Pa Iref ~2.1V peak (GSM1800@1900)
Mode ~1.8V OK?
Yes
PA & ant switch
EDGE troubleshooting
Figure 7: Transmitter EDGE troubleshooting
TX OK
Yes
Yes
Check
all power
levels,
OK?
Check output signal
No
on 500MHz span
Signal found on incorrect
frequency?
No
No
Check EDGE control
loop components
No
Replace faulty
components
Tune
No
TX power
levels,
OK?
Yes
Helgo EDGE
troubleshooting
Yes
Tune TX DAC values
Yes
OK?
No
Synthesizer
troubleshooting
Replace Helgo