Mp3 connection on radio R770

hello,
I've been trying to connect an Mp3 reader to the R770 radio (original on Freelander), here's how far I've gotten:

this is where the signal from the tape reader goes to the mainboard

here is the plug "unpluged"


on that place I conected a Aux Line-In like this to the mainboard


all the conections and welding is ok but I still get very much "noise" when I play music from the Mp3,
I've been told I have to weld a resistance and a zener to the Line-In to work as a "filter", now I need some help.

Thanks in advance
Miguel Baptista

10/10 for having a go at this. (solder, not weld)

I assume you have the source volume of the mp3 as high as it will go without distorting and controlling the volume with the R770. Also does the R770 have a dolby or NR button ?

Not sure if the R770 would control a cd multichanger, may be a better result picking up that audio line

Optimus Prime said:

10/10 for having a go at this. (solder, not weld)

I assume you have the source volume of the mp3 as high as it will go without distorting and controlling the volume with the R770. Also does the R770 have a dolby or NR button ?

Not sure if the R770 would control a cd multichanger, may be a better result picking up that audio line

Click to expand...

I've tried all the combinations of volume on both;
Neither dolby nor noise reduction;
LR part number STC50163 is the CD Autochanger for the Freelander but I've been told since the sistem is CanBus (got no idea what it means) it won't work.

feeding a Line-In through de CD input plug was my first attempt:
this is the back pff the R770


the CD input plug is the C plug
1-SDA
2-SCL
3-GND
4-MCS(MBR)
but besides conection 3-that stands for Ground I couldn't make it out to turn it into this

try page 7 "stereo upgrade"...I fitted this a month ago, the result is amazing and took only a few minutes to fit.

cable guy said:

try page 7 "stereo upgrade"...I fitted this a month ago, the result is amazing and took only a few minutes to fit.

Click to expand...

page 7 from where?

sorry, I should have said...on this site..you're on page one now, jump to page 7

cable guy said:

sorry, I should have said...on this site..you're on page one now, jump to page 7

Click to expand...

found it, btw it's on page 8 now, easy solution but besides having to use cig lighter for other stuff I dont like those Mp3 readers/Fm transmiters, was searching for a more permanent solution.

Put a 1K resistor in the positive of the left and right channels. If this doesn't pull the level down you could also add a couple more going to the ground on the player side of the first two resistors. This should pull the output down to tape head levels. You may find the sound is bass heavy? This is to do with the way the tape head is pre-amped and it's difficult to get round without having the unit in the workshop to run some tone tests. You may need to turn the bass down.