Nokia 105 Rm 908 Keypad Ways Site

When tracing a broken line, find an active button within the same series matrix group to run your jumper wire. Power Key / End Button Failure

Unlike modern smartphones with capacitive touchscreens, the Nokia 105 RM-908 uses a traditional carbon-pellet or metallic dome switch matrix. When these fail, the solution isn’t always to replace the entire keypad flex cable; often, the issue lies in the motherboard’s (the copper traces and connection points between the processor and the keypad connector).

A reading between means the track link to the processor is intact.

Please note that repairing or replacing the keypad requires technical expertise and specialized tools. If you're not comfortable with DIY repairs, it's recommended to seek professional help. nokia 105 rm 908 keypad ways

When a "way" is broken (due to a cracked PCB, corroded via, or lifted pad near the connector), the processor never receives the signal for that specific row or column, causing an entire line of buttons to fail.

This wire features an insulated coating that prevents accidental shorts against the ground shield or surrounding pads.

If the Keypad Filter IC is unavailable, "Direct Jumpers" to the CPU/PDSA can be performed, though this requires advanced soldering skills and a detailed schematic. The most common failure points are the filter capacitors near the keypad interface; removing these capacitors and checking if functionality returns is a common diagnostic step. When tracing a broken line, find an active

On the RM-908 board, the component responsible for scanning the keypad is typically a small CPU/IO expander or directly the main CPU. For keypad issues, we focus on the matrix lines at the or a dedicated Keypad IC (often labeled U400 or similar near the keypad ribbon connector).

Repair guides often focus on grouping non-working keys to identify the broken "way" or track: Power Button Issues

Place the PCB under a microscope or magnifying glass. Look for: A reading between means the track link to

| Key | Connection Point A | Connection Point B | | :--- | :--- | :--- | | | 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 | | ... | ... | ... |

You will need to apply liquid flux around the main IC shield, heat it with a hot air rework station at approximately 350°C, and gently to reconnect the keypad pads back to the circuit board. 6. Software Reset Alternatives

The Nokia 105 RM-908 utilizes a Matrix Keypad layout. The keys are arranged in Rows and Columns. To repair broken tracks, technicians must bridge the connection from the Key Dome to the corresponding Point on the Keypad IC or CPU.