Introduction: Hack Digital Radio, Replace the Volume Control

Picture of Hack Digital Radio, Replace the Volume Control

Few moths ago, my mother come back from Italy and brought me a digital radio in the form of an car (Porsche Cayenne ?)

it is cool, no ?

The problem, on every boot, the volume is set to 84% ... It's very noisy !!

I don't understand why each FM frequence are saved into the memory but is not the case for the volume ?

It is why i decide to try to control the volume from an external potentiometer

Step 1: Identifying the Amplifier Chip

Picture of Identifying the Amplifier Chip

After i have identified the amplifier chip : an MC4863 (Dual 2.2W Audio Amplifier) i download the datasheet to understan how the gain it is controled

I found the following text and image in the datasheet:

The first amplifier’s gain is externally configurable, while the second amplifier is internally fixed in a unity-gain

The datasheet talk about a resistor of 20Khom to control the external gain but on the PCB i have found only two resistors of 67Khom ... may be to have a gain > 1 ?

Step 2: Build a Dual Potentiometer From Two Traditional Potentiometer

Picture of Build a Dual Potentiometer From Two Traditional Potentiometer


The Chip MC4863 is a dual Audio Amplifier so that means it has two independent output signals ... which mean it require two different potentiometer in one package

I don't have one, so i build it one ...

Step 3: Fix the Dual Potentiometer

Picture of Fix the Dual Potentiometer

After the dual potentiometer is done, i fixed it on the car (I couldn't fix it where i wanted to fix it initially)

Step 4: Replace the 67Khom Resistors by the DIY Dual Potentiometer

Picture of Replace the 67Khom Resistors by the DIY Dual Potentiometer

It is very delicate to disolder SMD components because the PCB copper layer can unstuck

It is why i do this step at last

Step 5: The Final Result in the Video

Comments

makeosaurus (author)2016-04-24

Good idea!!

neo_xnitro (author)makeosaurus2016-04-24

Thanks ;)

About This Instructable

1,486views

11favorites

License:

More by neo_xnitro:Ikea Worklight (Portable)Hack digital radio, replace the volume controlstack ICSP breadboard adapter
Add instructable to: