Doesn´t Start - Ericsson I 888 Trouble-Shooting Instruction

3 Doesn´t start.
3.1
Attach a fully charged battery and press the On/Off-button. If the phone doesn´t
start, proceed to section 3.2. If the phone starts as normal when it is complete, but
shuts down in the trouble-shooting fixture, measure the current consumption. If it is
>1.5 A or as high as the current limit on the power supply, then N401 (class D, fig
3.1) is faulty and the phone can´t be repaired at this repair level. (Measure the resist-
ance between N401:14 and ground, it should be >10 kOhm, but if N401 is faulty it
usually is about 200 Ohm).
D610
If the phone starts, check the charging function by connecting a charger at the sys-
tem connector.If the charging doesn´t work, proceed to chapter 6 ("Charging"-
fault). Open the phone and make a visual check of the board. The side with the com-
ponents are shown in fig 3.1. Check the board for liquid damages and burned or dan-
ages pads at the system connector. Measure the resistance of R421 (0,1 Ohm, class
B, fig 3.1). After every repair of the charging function, you have to verify the
function using the method mentioned in section 6.1.1. Check the solderings on
D600 and D610 (Fig 3.1). As soon as the fault has been corrected, send the phone
back into the normal repair flow. If the phone starts and the values above are correct,
it is either without faults or there is an intermittent fault.
Find out if the phone will start by using the
On/Off-button.
C710
R725
N703
32
33
64
65
N701
N412
VDSP
N410
N411
4-00021-2/FEA 209 544/5.C
I888, Standard Electrical Repairs
VDIG
N702
B510
C692
1
128
97
96 D600
VRAD
VVCO
VRPAD
Fig 3.1
R421
1 28
N401
1
14
15
10
(42)