Repairing a Nokia 105 (RM-908) with a malfunctioning keypad typically requires identifying broken tracks or "ways" on the PCB and applying precise jumpers to restore connectivity Common Hardware Solutions for Keypad Issues
If specific keys are not working, it is usually due to a break in the circuit path. You can trace and repair these using the following methods: Power Key Solution
: If the device fails to turn on despite a good battery, technicians often look for a jumper path for the on/off key Keypad Jumper Guide
: For non-responsive keys or missing lines, a multimeter is used to test the keypad tracks for continuity. If a line is dead, a thin copper wire is soldered between the active pad and the corresponding circuit point on the board. Track Testing
: Keypad paths often run from the button pads to the CPU or specific resistors/capacitors. For instance, the C107 capacitor
is sometimes a missing or damaged part that affects RF and related board functions. Software & Operation Fixes
Sometimes, keypad "failure" is a software lock or a settings issue rather than a hardware break: Unlock Code
: If the keypad is locked and asking for a code, the default factory security code is typically Hard Reset
: If the keypad behaves erratically due to software bugs, you can perform a factory reset by entering on the home screen. Keypad Tones : If keys work but don't make sound, go to Menu > Settings > Tone settings > Keypad tones to adjust the volume. General Maintenance Tips
: Before soldering jumpers, clean the keypad PCB pads with isopropyl alcohol to remove carbon buildup or liquid damage. Battery Check
: Ensure the three metallic connectors on the battery line up perfectly with the phone's connectors to prevent power-related key failures. key or the button), or do you need a full circuit diagram image for the RM-908? Nokia 105 Dual Sim 4th Edition Feature Phone - How to Setup
so this is an 800 mAh battery uh as you can see on the battery. there look for the part where there the three metallic connectors. Unbox-d by Digit Nokia 105 user guide: Keys and parts - HMD
In the small town of Circuitville, there lived a legendary mobile technician named Aris. Known for breathing life back into old devices, Aris was often visited by people who refused to let go of their trusted companions. One rainy Tuesday, a traveler arrived with a Nokia 105 (RM-908). Its keypad was silent—some keys were stubborn, while others refused to respond entirely.
Aris didn't just see a broken phone; he saw a puzzle of broken paths. He shared the "story of the jumper ways" to help the traveler understand how to fix such a delicate machine: 1. The Tale of the Multimeter
Aris began by explaining that the heart of any keypad repair starts with the multimeter. He set his to the buzzer range and carefully probed the tracks on the board. nokia 105 rm 908 keypad ways
The Golden Rule: Every key has two points—a center point and an outer circle.
The Mission: If a key doesn't work, you must find where the connection (the "way") is broken. 2. Identifying the Paths (The "Ways")
He pointed to the intricate lines on the PCB, explaining that they are like roads.
Power Key Problems: If the phone won't turn on, Aris looks at the power key ways. On the RM-908, the center point usually carries the main supply from the power section, while the outer ring is often ground.
Missing Lines: If a whole row or column of keys fails (e.g., 1, 2, 3), it means a single "track" shared by those keys has been cut.
The Secret Series: Aris noted that each line has small resistors in series. If one side of a resistor has a signal (GR) and the other doesn't, a simple solder bridge (shorting it) can often restore the line. 3. The Legend of the Jumper
For the truly broken "roads," Aris performed the jumper solution.
Using a fine, insulated copper wire, he bypassed the broken internal PCB track by soldering one end to the source (often a component near the CPU or power IC) and the other directly to the keypad point.
A Pro Tip: If the path is entirely lost inside the board, the final solution is to "re-ball" or revolve the IC, though a jumper is the preferred "quick way" for most technicians. 4. The Final Awakening
Once the hardware was restored, Aris reminded the traveler of a few final "magic words" to ensure the software was just as healthy:
Hard Reset: If the keys work but the phone is sluggish, type *#7370# to erase and restore factory settings.
Master Code: When the phone asks for a security gate, the ancient pre-set code is almost always 12345.
The traveler left with a working phone, understanding that even when a path seems lost, there is always a "way" to jump back into connection.
Repairing Nokia 105 (RM-908) Keypad Issues: A Comprehensive Jumper Guide Repairing a Nokia 105 (RM-908) with a malfunctioning
Is your Nokia 105 (RM-908) acting up with non-responsive keys or broken tracks? Whether it’s a single button or an entire row failing, hardware issues on this classic model are common but often repairable with the right jumper "ways".
This guide covers the essential steps for diagnosing and fixing keypad malfunctions on the RM-908. 1. Initial Troubleshooting
Before opening the device, rule out software or minor physical blocks:
Clean the Pads: Dirt or moisture often gets under the keypad membrane. Clean the gold contacts on the PCB with isopropyl alcohol.
Check Keyguard Settings: Ensure the keypad isn't simply locked by going to Menu > Settings > Security > Keyguard.
Factory Reset: If the keys work but the phone is "stuck," use the hard reset code *#7370# (default security code is 12345). 2. Identifying Hardware Failures
If cleaning doesn't work, you likely have a broken "way" or track. Technicians use a multimeter set to Buzzer/Diode mode to test continuity between the key pads and the CPU or surrounding resistors. Common Keypad Symptoms:
No Power-On: Often caused by a break in the Red Power Key line.
Partial Row Failure: If keys like 1, 2, and 3 fail simultaneously, there is a break in the common supply line for that row.
Short Circuits: When one keypress triggers multiple characters or a phone shutdown. 3. Jumper Solutions and "Ways"
The Nokia 105 RM-908 uses a series of resistors and direct lines to the main IC.
The Power Key: The center point of the power button carries the GR (Ground Resistance) value. If this track is broken, you can jump it directly from the power section components on the PCB.
Series Resistors: Each keypad line typically passes through a small series resistor. If you find a resistor with a signal on one side but not the other, you can carefully "short" (bridge) the resistor with a small wire to restore the connection.
CPU Reballing: In extreme cases where multiple lines are dead and tracks are intact up to the main IC, the chip itself may need reballing to restore contact. 4. Step-by-Step Repair Process Disassemble: Carefully remove the back cover and battery. Restoring Carbon Pads
Test Tracks: Use a multimeter to find which specific "way" is missing its signal.
Apply Jumper: Using thin enameled copper wire, connect the dead pad to its corresponding test point or resistor.
Seal: Use a tiny bit of UV mask or tape to secure the jumper wire so it doesn't short against the metal shield.
You can find detailed visual jumper maps on tech forums or sites like Pinterest for RM-908 which often host specific track layouts. Nokia 105 (2023) User Guide - HMD
For the Nokia 105 (RM-908), "keypad ways" typically refers to the electrical pathways (tracks) on the circuit board that connect specific keys to the processor. Repairing these tracks is necessary when keys become unresponsive due to water damage or physical wear. Technical Repair & Jumper Solutions
When a track is broken, technicians use a "jumper"—a small wire—to bypass the break and restore connectivity .
Diagnosis: Use a multimeter in "buzzer" or diode mode to check for continuity on the circular keypad contact pads .
Key Groupings: Keys on this model are often grouped in rows or columns sharing a common line (e.g., keys 1, 2, and 3 often share a track). If an entire row fails, the fault is likely in a shared line leading to the main IC .
Power Key: The power button has a specific red-coded supply line on technical diagrams. If the phone won't turn on, a jumper is often taken from the power section directly to the center point of the power key .
Component Level: There are small resistors in series with the keypad lines. If you find a break, you can sometimes "short" (bridge) these resistors to restore the signal . Keypad Jumper Visuals
These diagrams highlight the common jumper points used to fix unresponsive keys:
Published by: Mobile Repair Hub
Difficulty Level: Intermediate (Soldering and basic schematic reading required)
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.
If multiple keys fail or ghost typing occurs: The issue is likely the Keypad Filter/EMI Filter IC.