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Toothman
08-22-2013, 10:57 PM
I have a hard wired backup camera that's been giving me fits. Was a nice clear picture a year ago but now has vertical lines running through half of the screen . The other half of the screen is pretty clear with slight interference. Was going to check the ground wire but have no idea where to look. Anyone know where the ground is usually made. The camera does gather some moisture occasionally but shows interference even when dry. Any ideas? Thanks

autostaretx
08-22-2013, 11:36 PM
If it's only affecting *half* of the screen, there are two (most) likely causes:
(a) a loose (or compromised by moisture) connector inside the camera.
The circuitry that says which part of the photosensor (CMOS) to "send now" is mis-addressing the segment of the chip it wants
(b) echos on the signal line running from camera to screen: the pulses that serve as "Hsync" and Vsync are causing ripples which as seen as signal by the screen. This can happen if the RCA plugs are corroded or weakly grabbed by the connectors.

A simple "poor ground" should affect the entire image.

good luck
--dick

shortshort
08-23-2013, 05:12 AM
Lemme translate that for you: You need a new camera.

autostaretx
08-23-2013, 04:16 PM
Lemme translate that for you: You need a new camera.

Well,... it could be the screen that's messing up (same reason as (a))

To really test what's at fault, you'd need a second screen (see if symptoms persist) or camera.

--dick
p.s. and (b) was the cable, not the camera

wires
08-23-2013, 04:27 PM
Three parts to this system:

1. Camera
2. Cables/connectors
3. Monitor

The first step is always to disconnect all connectors and check for obvious problems. Sometimes just disconnecting and reconnecting fill fix a problem.

Lacking fancy test equipment (scope...) the only way to be sure what is failing is substitution. I'm with shortstop, it's most likely the camera since the OP states that "camera does gather some moisture occasionally". Water on energized printed circuits tends to erode the circuit traces due to electrolysis. Cameras are fairly cheap so start there since it is likely damaged. One of mine did the same thing, my reinstall is detailed in T1N Write-Ups (http://sprinter-source.com/forum/showthread.php?t=26651).

Toothman
08-23-2013, 10:48 PM
Thanks guys. I took the face off the camera and pulled out the innards to have a look. I saw one wire that appeared firmly attached and saw no evidence of moisture damage in the form of rust or corrosion.