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Trouble Shooting Guide, Advanced
If the resistance is correct, replace the corresponding circuit, VDIG - N702, VDSP - N701.
If the resistance is too low, use the schematics.
Remove one component (or lift the pin/pins feeding the circuit) at the time that is fed from the
short circuit voltage and measure the resistance after removing it.
You have found the faulty component when the resistance is raising after removing.
Do not forget to mount all the components that have been removed.
You also should replace the circuits on which you lifted the pins.
The short circuit is usually due to D610, D600 or anyone of C600, C602-C610 for VDIG and
D900 or anyone of C900, C902-C906 for VDSP.
If any of the voltage is too high, replace the corresponding circuit.
Measurer the voltage VRAD, VVCO and VRPAD (+3.8 V
).
DC
If any of the voltage are incorrect, measure the resistance between ground and the faulty
regulator >10 Kohms.
If the resistance is correct, replace the corresponding regulator.
If the resistance is incorrect, use the schematics.
Remove one component (or lift the pin/pins feeding the circuit) at the time that is fed from the
short circuit voltage and measure the resistance after removing it.
You have found the faulty component when the resistance is raising after removing.
Do not forget to mount all the components that have been removed.
You also should replace the circuits on which you lifted the pins.
The most common fault is a short circuit at VRAD.
The short circuit is usually due to any of the 10nF-capacitors of the feed voltage or N450.
Check the amplitude of the MCLK, using the oscilloscope, at B510: 3 >0.7 V p-p.
You can also use the spectrum analyser to check the amplitude >1 dBm.
We propose the following settings for the oscilloscope: CF – 13MHz, SPAN – 1 MHz, RBW –
10 kHz, VBW – 10 kHz and SWEEP – 30 ms.
A fault of the clock can be due to L540, B510 or a short circuit in C542, D600, N301 or C301.
Sometimes is the fault due to N500.
Make sure the soldering at D600, D610 or D630 is correct.
If they are correct and all of the feed voltage and the clock are correct, the fault usually is due to
D600.
The fault can also be due to D610 or D630.
Try to program the phone between each replace.
Note! D630 can not be replace, since it demands advanced equipment and extensive calibrations
at board level that can not be done at this repair level.
2.5.1 The phone consumes more then 200 mA
Open the phone and check for liquid damage.
No further action should be taken for a liquid damaged telephone.
Make sure the pads of the system connector are not burned.
Attach the board to the fixture. Keep the board powered up using DCIO high.
Measure the voltage VDIG and VDSP (+3.2 V
).
DC
4/00021-3/FEA 209 544/18 B
11(121)
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