I have an 04 F-350 SRW CC. I have an Alpine 7in indash flat screen with a flush mount back up camera in my bumper. The camrea lasted 9mo not bad for a $30 camera. Well I ordered a new one and went to put it in and I am getting a very fast scrolling on my screen. I am stealing power for the camera from the 12v constant on the tralier harness. This is the process of elimination I have done so far. I have used a different camera that has its own power like a video camera and used the same video cord at the back of the truck and the screen looks perfect. So its not the video wire. I then tried the camera with long aligator clips right to the battery still using the video cord at the back of the truck and its still has the bad scrolling it almost looks like a ground loop. I then took the camera to the glove box where I have an Aux input to the screen for like an ipod and used power right from the batter to power the camera and still have the bad scrolling. A picture comes up so the camera is on but its so bad you cant really see anything. I called the company thinking bad camera and they sent me another free and told me to keep the old one and the new one is doing the same thing. So I am thinking its not the camera since both cameras are doing the same exact thing. The only other thing I can think to do is isolate the ground from the radio right to the battery as well but why would this start all of a sudden. Camera worked for 9mo then died all together now this. Any other ideas that I can do to try and figure out this issue? Really want to get it working as it makes backing up to the trailer so much easier and is nice to turn on while going down the road to see the tounge make sure nothings coming apart.

Thanks Ryan

 

Does it happen when you use it outside of the vehicle altogether? Inside your house, connected to your TV, and a power adapter, benchtop power supply, or a small sealed lead acid battery?
You're sure that the camera is expecting 12V right, not more or less?

 

I havent had a chance to try it on my tv in the house because the truck is the only 12v supply I have and I would have to get either a REALLLY long composite video cable to go into the living room or an extention cord with some aligator clips on the end and then there might be some voltage drop. The wiring schematic does specify 12v. I do not have a battery supply I can bring in the house unless i take a battery out the truck which I aint doin. I dont have a bench tester. I am trying to see if a buddy may have another 12v camera I can use to test on my truck and then we would know its my camera or my truck. I will try a friends camera and try getting this 12v camera on a different screen and a different power source to rule that out before I pull the dash to isolate the ground on the head unit. I just get the idea thats the culprit. Maybe some ground problem between the unit and the camera. Must be a difference. Thanks for the interest. Keep the ideas coming!

 

...or bring a small TV with a video input outside to the truck with a long extension cord? That should be more common?

 

Okay, to isolate the ground problem run the camera off the same power supply as your head unit (use your alligator clips on somewhere between that and the wiring harness). The other thought is that the composite video cable should already be grounding the camera through the braid. If you think that is actually causing the issue then insert the composite video connector halfway so that only the center conductor is connected, without the outer. If your grounding is good throughout, it should still continue to work.

I do that a lot with security cameras, float the video (AC signal) on top of the DC for the power supply and use one coaxial cable to simultaneously power the camera and pass the video signal. The outer conductor braid serves simultaneously as the reference ground for the video and the return 'negative' for the power. (Capacitors on the ends to block the DC so you don't blow up the video equipment.)

It would be way easier to provide suggestions if I could see the set up and the equipment being used, but in absence of that, I'll just keep throwing in ideas.

 

Just another thought. Could it be a sync problem between the new camera and the orignal display? Since your using straight 12vdc I do not think it would be noise if the engine is not running. Just thinking out loud.

 

Thanks for the help guys. JH818 I am going to try and locate a small tv to bring out. Thats a good idea. Trent310 I tried to float the ground on the video cable and im still getting the scrolling even with the engine off. Also Trent310 I found out that the input must not be capacitor isolated because I tried that well now the aux input in the glove box doesnt show anything but a black picture. The rear of the truch is still showing the scrolling effect. So now I don have video in the glove box so that blows. I think I am going to try and have my buddy pull up next to my truck and use his batt to power the camera. If it works I am not really sure what that means for a fix but maybe it will tell me something. Thanks for the help keep it coming!