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Trouble Shooting Guide, Advanced
You have found the faulty component when the resistance is raising after removing.
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.
Measure the power reset at C710 +3 V
.
DC
If it is lower, lift up N703 pin 1 and try again.
If the voltage is raising, the fault is due to N703.
If the voltage still is too low, the fault usually is due to C710, C718 or R704.
Measure 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.
2.5
The phone can be programmed, but does not start
afterwards or is troublesome in the flash programmer
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
If any of the voltage are too low, measure the resistance to ground,
VDIG >500 ohms, VDSP >25 Kohms.
4/00021-3/FEA 209 544/18 B
10(121)
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