GH688,GA628, Standard Electrical Repairs
4/00021-2/FEA 209 544/1.G 19 (112)
* If the resistances from any of the voltages to ground are too low, send the
phone to the next level.
Make sure that there are no faulty solderings on D600, D610 and D620.
• If the solderings look good, replace D610 (class A).
* If that doesn’t help, first replace D600 (class B) and then D620 (class A).
Try to program the phone in the flash programmer for every circuit you
replace.
3.4.3 Consumes more than 200mA.
Open the phone and check for liquid damage.
Make sure that the system connector pads aren’t burnt.
Insert the board in the fixture. Start it up and keep it going by keeping DCIO high.
Check VDIG and VDSP (~3.2V, fig. 3.2).
• If any of the voltages are too low, measure the resistance from it to ground
(VDIG >500 ohms, VDSP >25 kohms).
* If the resistance is correct, replace the corresponding circuit (VDIG – N702
– class A, VDSP – N701 – class A).
* If the resistance is too low, send the phone to the next level.
• If any of the voltages are too high, replace the corresponding circuit.
Check VRAD, VVCO and VRPAD (~3.8V, fig. 3.6).
• If all three voltages are incorrect, measure the resistance from N450 pads 8, 11,
12, 13 and 14 to ground (0 ohms).
* If the resistance is too high there is a foil damage and the phone should be
discarded.
* If the resistance is correct, replace the circuit and eventually transistors
(V450, V451, V452, all class A).
• If one or two of the voltages are incorrect, measure the resistance to ground (>50
kohms).
* If the resistance is correct, replace the corresponding transistor.
* If that doesn’t help, replace N450 (class A).
* If the resistance from any of the voltages to ground is too low, send the
phone to the next level.
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