On/Off Problems - Ericsson T28S Troubleshooting Manual

3 On/Off Problems

3.1 Type of fault
Make a general visual inspection of the phone.
Make sure the battery connectors are intact, clean and fully functional.
Measure the resistance from VBATT to ground at the Battery Connector (Fig.3.1). It should
be more than 20 kohms. If the resistance 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.
Make sure there is no liquid damage at the system connector.
Replace if needed.
Insert a fully charged battery and press the On/Off key.
If the phone starts without the On/Off key being pressed, go to section 3.2.
If the phone starts, check the charging function by connecting a charger to the system
connector.
If the charging function is faulty, go to chapter 6 Capacity/Charging Problems.
If the phone starts (lights the background illumination, asks for SIM/Pin, seeks net...) there is
probably nothing wrong with the phone or the fault is intermittent.
If the phone does not start, insert a dummy battery and keep the On/Off key pressed.
If the phone consumes more than 50mA, go to section 3.3.
If the phone consumes 15-30mA, go to section 3.4.
If the phone consumes less than 15 mA, go to section 3.5.
4/00021-2/FEA 209 544/19 E
Fig. 3.1
Trouble Shooting Guide, Standard
10(29)