Ericsson T18s Trouble-Shooting Instruction page 25

Check the solderings at pins 13-17 of N800 (fig. 4.2).
If the fault really is electrical and the above mentioned components aren't faulty,
replace C818 and C819 (class A, fig. 4.2).
Measure the resistance from one of the X830 pads to the other (~28 kohms, fig.4.2).
• If the resistance is incorrect, replace C815 (class A, fig. 4.2).
Measure the resistance from pad 1 of X830 to ground (fig. 4.2, ~27 kohms).
• If the resistance is incorrect, measure the resistances of R812 and R814 (~470
ohms, class A, fig. 4.2).
* If the resistance is correct, measure the resistance from pad 1 of X830 to pin
13 of N800 (<1 kohms, fig. 4.2).
* If the resistance is to high there's a foil damage and the phone is to be
discarded.
Measure the resistance from pad 2 of X830 to ground (fig. 4.2, ~470 ohms).
• If the resistance is too low, replace C820 (class A, fig. 4.2).
• If the resistance is too high, replace R820 (~470 ohms, class A, fig. 4.2).
If the fault remains, send the phone to Advanced electrical repairs.
4.4 Both the earphone and the microphone out
of order.
Open the phone and check for liquid damages.
Make especially sure there's no dirt or oxide between the components below the
dome foil (components in fig. 4.1) and at the system connector pads.
Clean the circuit board if needed using alcohol and a brush.
Assemble the phone and test it again as described in section 4.1 (call a reference
phone).
If the fault remains, open the phone. Give the board power and start it up without the
system cable connected by pressing the On/Off key.
Measure the VDIG voltage (~3.2V, fig. 4.3).
• If the voltage is incorrect, proceed to chapter 3, "Doesn't start"-fault.
4/00021-2/FEA 209 544/12.B
T18s, T18sc Standard Electrical Repairs
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