Ericsson T18s Trouble-Shooting Instruction page 41

If the fault still remains, send the phone to Advanced electrical repairs.
Oscilloscope measuring.
Measure the voltage VVIC (suitably on a multimeter) at D901 pin 1, it should be
3.2V . If it is missing, replace C901, C910 and R920 (class A).
Set the oscilloscope for DC-measuring 1V/square and time setting Roll.
SIMVCC:
Measure at the SIMVCC-pad (see Fig. 7.1) while starting the phone. The phone
sends 5 pulses with an amplitude of 5 V at start up (see Fig. 7.2).
• If SIMVCC is missing at J603 pad 1, do the same test again, as above, but at
D901 pin 4 (see Fig. 7.1). The signal (SIMPWR) should look the same but with
the amplitude 3.2 V.
* If the signal (SIMPWR) is missing, do the same test, but at D600 pin 72.
* If SIMPWR is missing here too, replace D600 (class B).
* If SIMPWR exists (at D600 pin 72), then there is a foil damage and the
board has to be discarded.
* If SIMPWR exists at D901 pin 4, measure SIMVCC at D901 pin 14.
* If it is missing, replace first C908, C909 then D901 (class A).
* If SIMVCC exists at D901 pin 14, there is a foil damage between D901
pin 14 and J603 pad 1.
4/00021-2/FEA 209 544/12.B
T18s, T18sc Standard Electrical Repairs
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