I got tired of using that crappy FM transmitter to play my songs on my mp4 player through the car’s stereo system. The quality just plain sucks when you crank up the volume. And the interference coming from the neons and alternator adds up to my frustration. I guess it took me RM60 to realise that a simple FM transmitter is just not suitable for any sort of audio transmission in a vehicle.
It would be simple just to give up and abandon the idea of putting the mp4 player in the car. But with 1GB of storage space for close to 19 hours of playback (mp3 encoded at 128kbps), it’s not going to happen. So I took out the player for a major surgery.
I feel that there is a need for a disclaimer here just in case someone tries to sue me. Here goes: I will not be responsible for whatever you do to your player. I will also not be taken responsible if you somehow screw up your whole player. I am merely providing information and instructions on how such a DIY can be accomplished. Oh, and you ARE going to void your warranty. Proceed only if you are sure of what you are doing.
This is my Pioneer headunit. Model is DEH-1650.
First we remove the top cover. Then marvel at how the slot loading cd drive works…
Now remove the cd drive to reveal the circuit board underneath it.
The trick is to somehow inject the audio from the mp4 player into one of the inputs of either the radio or the cd drive. In this case I chose the radio. So now when I turn on the radio, the audio from my mp4 player will be injected into the system and I will hear my songs on my mp4 player instead of the radio. Don’t worry, you still get to listen to your radio after you are done with this.
This is the radio tuner module. It contains everything needed for FM and AM reception. So there must be pins for the radio’s output (audio).
And yes, there are! Labeled clearly here are the left and right channel output of the radio module. Now let’s find a way to tap into it.
After much tracing through the circuit board, I found these 3 jumpers. These connect the radio module’s output to the player’s amplifier. I have labeled them R (right), L (left) and G (ground) for my own convenience. I cut all 3 of them so the audio from the radio won’t interfere with the audio from my mp4 player.
This is how the underside looks like. We’ll zoom in to the chip on the left.
The pins circled in red are the pins that you must connect your mp4 player to. The audio ground can be connected to the ground of course.
I connected my wires this way. The wires will then be connected to a 3.5mm audio jack.
What is not shown here is how to get the radio functionality back. All you have to do is wire a 2 pole relay to the jumpers that were cut and mount a switch to the dash. When you want radio, flip the switch and the relay will help you connect the jumpers back.
Of course, an easier way is to use the FM radio on your mp4 player. There! Problem solved!
This mod is really impressive because of the quality of the sound it delivers. No more annoying hisses or pops and no more static. Just clear and loud music. Wish I have thought of this earlier… Continue reading