Gently use a hobby knife to scrape away the green solder mask covering the target trace line if you are soldering directly to a trace rather than a pad.
The black carbon pads under the rubber sheet or the metal domes become oxidized and dirty, blocking electrical contact.
Identify the open circuit and bridge the row contacts together. Vertical column failure Fractured column trace line on the PCB nokia 105 rm 908 keypad ways
A common issue is the or specific functional keys failing.
| Symptom | Possible Cause | Fix Using Keypad Ways | |--------|----------------|------------------------| | Single key not working | Broken trace or dirty contact | Clean pad; jumper trace from keypad pad to next test point | | Entire row not working | Open row line | Trace row line from processor to first key, bridge broken way | | Entire column not working | Open column line | Similar – jumper column trace | | Multiple random keys | Short between ways | Check for solder bridge or corrosion | Gently use a hobby knife to scrape away
If the 1, 2, or 3 keys still function normally, connect a jumper wire from the inner point of the Left Selection key to the center core of the 1 key to quickly restore the signal chain. Professional Soldering Tips for Micro-Jumpers
If the phone charges but refuses to power on via the button, the center core line is broken. Vertical column failure Fractured column trace line on
Use Isopropyl Alcohol (IPA) and an anti-static brush to clean away residual flux, preventing cross-key shorting or long-term corrosion.