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Trouble Shooting Guide, Advanced
We propose the following settings on the spectrum analyser while measuring:
CF- 902.4 MHz, SPAN- 0 MHz, RBW- 300 kHz, VBW- 100 kHz and Sweep- 0.8 ms.
Check if there is an output power, 30- 35 dBm, at the antenna-plate using the spectrum analyser.
If the output power is correct, the phone is probably without fault.
Try the phone in the test again.
If there is no switched output-power at all or if it is too low, go to chapter "No serv".
If the transmitter does not lock on, start the transmitter in static mode again and change the
settings for the spectrum analyser to:
772.4 MHz, SPAN- 200 MHz, RBW- 10 kHz, VBW- 10 kHz and Sweep- 30ms.
Check the frequency and the amplitude of the LO-signal at N303 pin 1 ~ -7dBm.
If the amplitude and the frequency are correct, go to section 5.2.1.
If the frequency is correct, but the amplitude is too low, check the feed voltage at N303 pin 6
+3.6 V
.
DC
If the voltage is correct, replace N303.
If the voltage is incorrect, check VVCO +3.8 V
, SYNTON_GSM +3.8 V
, and V305 with
DC
DC
the belonging components.
If the amplitude is correct, but the frequency is incorrect, the fault usually is due to N301.
It can also be due to N303 or D600.
If the signal is several MHz wide, replace C318.
To make a more accurate frequency measuring, try to lower SPAN to 1 MHz.
GSM 1800:
Start the transmitter in static mode at channel 699 1747.4 MHz, and check the amplitude and the
frequency.
If the frequency is misplaced, try to lower the "Adjust sweep current" until the frequency of the
transmitter has locked on.
We propose the following settings on the spectrum analyser while measuring:
CF- 1747.4 MHz, SPAN- 200 MHz, RBW- 10 kHz, VBW- 10 kHz and Sweep- 30 ms.
If the transmitter locks on start the transmitter in switch mode at channel, 699, with DAC 7
value at "FF".
We propose the following settings on the spectrum analyser while measuring:
CF- 1747.4 MHz, SPAN- 0 MHz, RBW- 300 kHz, VBW- 100 kHz and Sweep- 0.8 ms.
Check if there is an output power, 28-32 dBm, at the antenna plate using the spectrum analyser.
If the output power is correct, the phone is probably without fault.
Try the phone in the test again.
If there is no switched output power at all or if it is too low, go to chapter "No serv".
If the transmitter does not lock on, start the transmitter in static mode again and change the
settings for the spectrum analyser to:
1669.6 MHz, SPAN- 200 MHz, RBW- 10 kHz, VBW- 10 kHz and Sweep- 30ms.
Check the frequency and the amplitude of the LO-signal at N302 pin 1 ~ -7dBm.
4/00021-3/FEA 209 544/18 B
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