Ericsson T28S Troubleshooting Manual page 11

3.2 Starts immediately after inserting a battery
Open the phone and check for liquid damage.
Replace the dome foil.
3.3 Consumes more than 50mA
Measure the resistance from VBATT to ground at the battery connector (Fig. 3.1). It should
be more than 20 kohms. If it is less, usually only a few ohms there is probably a short circuit
in N400.
If there is a short circuit in N400, send the unit on according to the local company directives.
Open the phone and check for liquid damage.
Power up the board and press the On/Off key.
Measure the voltage on V500, at the pin close to N700. It should be more than 4.10 V.
If the voltage is 3.7 V replace V500.
Try to flash the signal program into the phone.
If the fault remains, send the unit on according to the local company directives.
3.4 Consumes 15-30mA
Try to program the phone in the flash programmer.
Open the phone and check for liquid damage.
If programming the phone is impossible measure the resistance over R629 (10 kohms).
If the resistance is incorrect, replace R629.
If the resistance over R629 is correct measure the resistance over C615. It should be more
than 40 kohms.
If the resistance is less, replace V607.
If that does not help, replace C615.
If the resistance over C615 is correct, replace D610.
If the fault remains, send the unit on according to the local company directives.
4/00021-2/FEA 209 544/19 E
Trouble Shooting Guide, Standard
11(29)