Sanyo 4920 Keypad Mod

Replacing the dull green LEDs for brilliant white.

I recently purchased a Sanyo RL-4920 Vision phone.

The phone is loaded with features and long battery life.

It also had a great color screen.

But...and ugly dull, uninspired green keypad.

After opening the phone, and counting the needed LEDs I ordered 12 LEDs from www.lsdiodes.com

It cost less then $10 for the LEDs needed to complete this mod. (including shipping)

Now it was time to crack the phone back open.

The phone has special Y shaped screw heads, but they can still be opened with the properly sized screwdriver.

Once open and taken apart I can remove the keypad for soldering.

There were actually four extra solder pads for more LEDs, but they were not installed.

I installed two of the extra LEDs, as I lost one LED into my carpet.

I removed one LED and tested to make sure the orientation and power would light the white LEDs.

 

Once all the LEDs were replaced, they looked good.

But they were just as bright as the green LEDs.

The LEDs I ordered take 35milliamps of power, run at 3.6 volts, and have a brightness of 200MCD.

(VERY Bright for surface mount LEDs)

The solution was to calculate the correct resistor value needed to run all the LEDs in parallel. (A total of 350mA)

The resulting value was only 1.2ohms.

I decided to use a 2.2ohm resistor.

The resistor I installed is a normal resistor, and is held inside the rubber tube at the bottom of the phone.

It is just large enough to fit into some empty space next to the phone's mic.

Now the LED are running at their full brightness.

Also note, that they will run warmer, and consume much more battery power then the original LEDs.

The original LEDs consumed about 100mA of power total. 

These LEDs consume 350mA of power.

This phone however has 1 week of standby power, and 5.5hours of talk time.

So the extra power needed shouldn't hurt the phone too much.

Here is a night shot showing the LEDs.

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And another.

The LEDs are the only source of light in this image.

They are more then enough for a good flashlight.

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With the phone put back together you can see that the keypad now matches the screen, both in color, and brightness.

It has increased the look of the phone considerably.

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At night the keypad is clear and easier to read.

Also note the middle joy-button is not lit-up.

Where originally it was barely visible at night.

The final image is below:

-If you do not see the navigation bar click here-