Nokia 105 Rm 908 Keypad Ways

Set your multimeter to continuity (beep mode).

The Nokia 105 (RM-908) keypad functions through a matrix of tracks (lines) that connect to the main CPU/Power IC. When specific keys fail, it is usually due to a broken track or "way" that needs a jumper to restore the connection. Hardware Troubleshooting (Keypad Ways)

For the RM-908, the keypad is organized into "rows" and "columns." If multiple keys fail together (e.g., 1, 2, 3), it indicates a break in a shared line.

Multimeter Testing: Set your multimeter to Buzzer/Continuity mode. Test from the center point of a non-working key to the center point of another key in the same row/column to see if the track is continuous. Common Jumper Solutions: nokia 105 rm 908 keypad ways

Power Key: If the phone won't turn on, check the red-marked track for the power button. This line often runs through a small resistor near the CPU.

Shared Lines: If a group of keys like 4, 5, 6 fails, trace the common track. You may need to jump a wire from a working key in that group to the non-working ones.

IC Issues: Since the RM-908 uses a single integrated chip for keypad control, if tracing and jumping don't work, the CPU/IC may need to be re-balled or heated. Essential Keypad Shortcuts & Operations Key Combination Lock Keypad Select Go to > Lock keypad. Unlock Keypad Press the End key and select Unlock. Flashlight On From home screen, quickly press Scroll Up twice. Flashlight Off Press Scroll Up once. Switch Case Press # repeatedly to cycle through ABC, abc, and 123. Special Chars Press and hold *. Factory Reset Dial *#7370# (Default code: 12345). Nokia 105 (2023) User Guide - HMD Set your multimeter to continuity (beep mode)

If all rows/columns are open or shorted, suspect cracked BGA joints under CPU. Reball using 0.35mm stencil and leaded solder.

In the Nokia 105 RM-908, the keypad lines often run through protective components (EMI filters) or directly to the CPU. If these filters get damaged due to voltage spikes or water, the keys stop working.

Technicians should use a multimeter in continuity mode to trace connections. If a track is broken, use insulated jumper wire (0.10mm) to bridge the gap. If all rows/columns are open or shorted, suspect

| Key | Connection Point A | Connection Point B | | :--- | :--- | :--- | | Call (Green) | Row 1 | Col 1 | | End (Red) | Row 5 | Col 1 | | D-Pad Up | Row 1 | Col 2 | | D-Pad Down | Row 2 | Col 2 | | D-Pad Left | Row 3 | Col 2 | | D-Pad Right | Row 4 | Col 2 | | D-Pad Center | Row 5 | Col 2 | | Soft Keys (L/R) | Row 1/2 | Col 3 | | Digit 1 | Row 1 | Col 4 | | Digit 2 | Row 1 | Col 5 | | Digit 3 | Row 1 | Col 6 | | Digit 4 | Row 2 | Col 4 | | ... | ... | ... |

(Note: Exact column/row assignments may vary slightly by PCB revision; always verify with a schematic diagram if available).