Trouble Shooting Guide, Advanced
4/00021-3/FEA 209 544/25 C
Ericsson Mobile Communications AB
24(78)
~-47 dBm on pin 2 of Z200. If the signal is missing the fault can be due to N200, C205 or
L203.
~-50 dBm on pin 10 and 11 of N300. If the signal is missing the fault can be due to Z200,
C204, C206 or L202.
Measure the RX-signal out from N300, use the oscilloscope:
67.7 kHz: ~1.0 V p-p at C123, C124, C125 and C126.
If only some signal is missing check the corresponding resistor and capacitor.
If there are no signals out from N300, check VHOM at pin 5 and 13 of N300.
If VHOM is correct the fault is due to N300.
If all signals are correct the fault is due to D600.
7.2.8 For GSM 1800:
Set Radio in RX Static mode on channel 699, Fig. 7.3.
Static RX is active after you have clicked on the Apply-button.
Fig.7.3
Set RX signal from the GSM test set to 1842.6 MHz and amplitude –40 dBm and with
modulation of ones (11111).
Make sure the RX amplitude really is –40 dBm on the antenna connector.
Raise or lower the amplitude on the GSM- test set if necessary.
We have been using following settings on the spectrum analyser when measuring the
transmitter:
CF- 1842.6 MHz, SPAN- 1 MHz, RBW- 10 kHz, VBW-10 kHz and Sweep- 30 ms.
Follow the RX-signal from the antenna to N300. The signal will have two peaks, that to the
right shall be measured (Fig. 7.2).
The attenuation of the signal over N200 is approximately 7 dBm, and over Z201 is
approximately 4 dBm.
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