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PF768, Standard Electrical Repairs
• If there isn't, check the resistances from H622 pad 6 to V608 (the VLCD marked
pin in fig. 5.2, ~0 ohms) and from pad 5 of H622 to ground (~0 ohms).
* If any of the resistances are too high there's a foil damage and the phone is
to be discarded.
2
• If the I
C-DATA or the I
at C600 (~3.2V, fig. 5.2)
* If the VDIG voltage is incorrect, proceed to chapter 3 ("Doesn´tstart"-
fault).
* If the VDIG voltage is correct, measure the resistances of R619 (~2.2
kohms, fig. 5.2), R620 (~2.2 kohms, fig. 5.2), R615 (~10 kohms, fig. 5.5) and
R616 (~10 kohms, fig. 5.5, all of class A). Check the solderings of D600 pins
3 and 4 (fig. 5.1).
* If all the resistances and the solderings are correct, replace D600 (class
B).
5.4
The display is black (all the segments are
"lit" and you can sometimes make out
what it's displaying).
Open the phone and check for liquid damages.
Give the board power and start it up by pressing the On/Off key. If the phone shuts
itself down after a few minutes, keep it running by keeping DCIO high.
Check the VDIG and VANA voltages (~3.2V, fig. 5.2).
• If any of the voltages are too low, measure the resistance from it to ground
(VDIG>500 ohms, VANA>25 kohms).
* If the resistance is correct, replace the corresponding circuit (VDIG – N702,
VANA – N700, both of class A).
* If the resistance is too low there's a short circuit in one of the circuits fed by
the regulator. Send the phone to the next level.
• If any of the voltages are too high, replace the corresponding regulator.
If the fault remains, proceed to section 5.3 (nothing shows in the display or the dis-
play has low contrast).
4/00021-2/FEA 209 544/11.C
2
C-CLOCK voltage is missing, check the VDIG voltage
32
(68)
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