Ericsson T18s Trouble-Shooting Instruction page 28

Open the phone and check for liquid damages especially around pads 1, 2 and 4 of
the system connector pads (J602, fig. 4.4).
Measure the resistance from pad 2 of J602 (fig. 4.4) to ground (>30 kohms).
• If the resistance is too low (short circuit at ATMS), replace F604 and C669 (both
of class A, fig. 4.7).
Measure the resistance of C850 and C851 (both are >100 kohms, in fig. 4.2 and of
class 2).
Make sure R830, C835, R825, C810, R802, R805 C812 and R803 (class A, fig. 4.2)
are mounted at the circuit board.
Check the solderings of N800 (fig. 4.2).
Give the board power and start it up without the system connector connected by
pressing the On/off key.
Measure the voltage at pad 2 of J602 (ATMS, ~3.1V, fig. 4.4).
• If the voltage is incorrect, measure the VDIG voltage at the marked side of R830
(fig. 4.2, ~3.2V).
* If the VDIG voltage is incorrect, proceed to chapter 3, "Doesn't start"-fault.
* If the voltage is correct, check the resistances of R830 (~470 ohms, class
A), R825 (~3.3 kohms, class A), C835 (>1 kohms, class A) and C810 (>5
kohms, class A, all four in fig. 4.2).
• If the voltage at pad 2 of J602 is correct, check the resistances of C810 (>5
kohms), C812 (>5 kohms), R802 (~10 kohms), R805 (~15 kohms) and R803 (~1
kohms, all of class A and in fig. 4.4).
If the fault remains, send the phone to Advanced electrical repairs.
4.6 Handsfree speaker out of order.
The fault occurs when there's an interrupt in the audio path from the N800 to the
handsfree speaker (connected through the system connector). The audio path is
shown in fig. 4.6.
4/00021-2/FEA 209 544/12.B
T18s, T18sc Standard Electrical Repairs
Fig. 4.6
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