Table of Contents
Advertisement
Power
level
0
6
7
8
9
10
15
If the output power value is higher than in Table.17.3. go to section 17.2.
If the output power value is lower than in Table.17.3. go to section 17.3.
NOTE! You have to program the phone with test program before calibration or trouble-
shooting.
17.2 The output power is too high
When the output power is too high, usually a few dBm over the limit, it usually is due to a
change in characteristic, because of ageing, in some of the components in the power regulation.
The same thing happens when you replace e.g. N401, N450 or N800.
The only thing necessary to do is a new power calibration, a part of the Radio calibration in
EFRA.
17.3 The output power is too low
If the output power is only a little to low, not more then 2 dBm, the fault can be due to a change
in characteristic, because of ageing, in some of the components in the power regulation.
The fault can also be due to a faulty back cover or antenna connection.
Try to perform a new power calibration, a part of the radio calibration in EFRA.
If the power calibration failed or the output power is several dBm to low, open the phone and
check for liquid damages. Make sure the antenna connection (X101) is without fault.
Give the board power and start it in the test program.
Measure the voltage at C853 +1.2 V
If the voltage is lower, replace the capacitor.
For GSM 900:
Start the transmitter in switch mode at channel 62 with DAC 7 value at "FF".
Check if there is enough output power, 30- 35 dBm, at the antenna connector, use the spectrum
analyser.
4/00021-3/FEA 209 544/18 B
GSM1800
Output
Tolerance
power
(dBm)
(dBm)
30
±2
18
±3
16
±3
14
±3
12
±4
10
±4
0
±5
Table.17.4
.
DC
Trouble Shooting Guide, Advanced
75(121)
Advertisement
Table of Contents
