Hi, I would like to add a stereo input on my JVC RV-B70 for my MP3 player. Does anyone know where I can find schematics because there are none in user guide. Thank you.

jvc does not sell it. so only used parts now. ask them ?
and using ebay ,you might get lucky
it is not a computer. (it's a BOOM box stereo noise maker)

JVC re-invents portable stereos with the RV-B90GY Kaboom. It's the highest power portable
stereo ever offered;
or goggle the while earth for it.
battery cover
JVC RV-B90GY we sell no parts here, all we can do is point to the obvious.

1. google
2. ebay
3. ask maker.

I am thinking you can connect with a 3.5 m m. Jack, with left right input jacks connected to it. Going to give it a try. Also might try the phone the same way.

take off all the knobs and it should come apart

How do I sinc my iPhone to the cd player or how do I sinc cd player to my phone

if the deck doesnt have an auxilliary input or usb input then the only way to get sounds to it and through it is going to be by using an fm modulator that will broadcast your mp3 tunes through an fm signal that you choose and simply tune you radio to the station that you chose to broadcast through.

Try turning the volume lowwer on the mp3 player and higher on the head unit. The radio is trying to amplify an amplified sound which is why you are getting distortion.

If it has a aux input at the back you can get a dock and that will let you plug it into your system.

Your car stereo accepts a "mini jack" input on the front faceplate and it is the same connector as the headphone output on the other end for the mp3 player.
Radio shack has them
http://www.radioshack.com/product/index.jsp?productId=3371342

I’m happy to assist further over the phone at https://www.6ya.com/expert/dan_91204789c5bd4b93

You have to enable "Line in" in the Stereo menu. Once you enable it when you press CD/CD-CH it should change to "Line In" and display Line in on the screen. Check the manual on how to enable line in...