Ericsson T18s Trouble-Shooting Instruction page 18

3.4.3 Consumes more than 200mA.
Open the phone and check for liquid damages.
Make sure the pads for the battery connector and system connector aren't dirty, oxi-
dised or liquid damaged.
Put the board in the fixture, start it up and keep it running by keeping DCIO high.
Check the VDIG (~3.2V) and VCORE (~2.5V, both in fig. 3.3) voltages.
• If any of the voltages are too low, measure the resistance from it to ground
(VDIG>48 kohms, VCORE>40 kohms).
* If the resistance is correct, replace the corresponding regulator (VDIG –
N702, VCORE – N700, both of class A).
* If the resistance is incorrect, send the phone to Advanced electrical
repairs.
• If the VDIG and VCORE voltages are correct, check the VRAD (~3.8V), VVCO
(~3.8V), VRPAD (~3.2V, all in fig. 3.3) voltages.
* If any of the voltages are too low, measure the resistance from it to ground
(VRAD and VVCO>100 kohms, VRPAD>40 kohms).
*If the resistance is correct, replace the corresponding regulator (VRAD –
N480, VRPAD – N702 and VVCO – N470), all of class A).
* If the resistance is too low there's a short circuit in one of the circuits fed
by that voltage. Send the phone to Advanced electrical repairs.
* If the voltages are correct, measure the resistance from VBATT to ground
(>500 kohms, fig. 3.1).
* If the resistance is incorrect, send the phone to Advanced electrical
repairs.
4/00021-2/FEA 209 544/12.B
T18s, T18sc Standard Electrical Repairs
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