ℹ️ To enable USB mode, you must apply +5V to TP3 after connecting the battery, or the phone stays in charge-only mode.
These are the critical communication lines. In the RM-908, these points are often found near the CPU or charging port area on the PCB. Technical Applications Nokia 105 Rm 908 Usb Pinout
| Symptom | Likely Cause | Pinout Check | |---------|--------------|---------------| | No charging | Broken VBUS or GND trace | Measure continuity pin1 → charging IC | | PC not detecting phone | D+/D- not connected to CPU | Check series resistors (22Ω typical) | | Phone shows "USB connected" but no function | Firmware limitation | Not a pinout issue | | Overheating while charging | Short between VBUS and ID or GND | Inspect pin4 (ID) – should not be shorted to VBUS | ℹ️ To enable USB mode, you must apply
This is why a standard USB cable plugged into a computer or even some USB chargers may not charge the Nokia 105 RM-908 – the phone does not see the ID pin pulled low correctly. Technical Applications | Symptom | Likely Cause |