Transmitter Troubleshooting Diagram - Nokia RH-30 Series Troubleshooting Instructions

Transmitter troubleshooting diagram

ICQ: 343183001 QQ: 35070846 Email: Serviceic@yahoo.com.cn
TX Troubleshooting
Check output signal level:
+32...+33dBm@836.6MHz (GSM850)
+32...+33dBm@897.4MHz(GSM900)
+29...+30dBm@1747.8 and 1880MHz
+32...+33dBm@897.4MHz (GSM900)
(GSM1800&1900)
+29...+30dBm@1747.8MHz and 1880MHz
OK?
(GSM1800 and 1900)
No
TX signal found?
Yes
Check with RF probe signal level on
PA input: >=0dBm
OK?
Yes
Start TX power level tuning and check tuned DAC values:
Highest level ~670...850(GSM900); ~580...700(GSM1800&1900)
Highest level ~670...850(GSM850/900);~580...700(GSM1800/1900)
Yes
Lowest level ~170...200(GSM900); ~180...220(GSM1800&1900)
Lowest level ~170...200(GSM850/900);~180...220(GSM1800/1900)
Base level ~140...170(GSM900); ~135...165(GSM1800&1900)
Base level~140...170(GSM850/900);~135...165(GSM1800/1900)
Major differences?
No
Check control voltage with
oscilloscope:
PA Ctrl voltage >1.5V peak
OK?
Yes
PA & ant switch
troubleshooting
Figure 3: Transmitter troubleshooting
Yes
OK?
Check output signal
No
on 500MHz span
Signal found on incorrect
frequency?
No
No
No
TX OK
Yes
No
Check
all power
levels,
OK?
Yes
Helgo
troubleshooting
Yes
Check control loop
components
OK?
No
Replace faulty
components
Tune
TX power
levels,
OK?
Synthesizer
troubleshooting
Tune TX DAC values
Yes
Replace Helgo