Alfredbra

after reading through all the threads on screen flicker and alternator whine I am still suffering!

Currently my screen is connected using VGA and powered off my M2-ATX PSU and I am getting these horizontal lines through the screen ONLY when the car is on.

I have tried grounding the case and vga cable which do slightly improve the picture however it is quite noticable at night time. This is my 2nd setup in a differnt car (Holden Monaro 2002) with all new parts. Seems like there is some sort of high frequency noise comming through the VGA. There is also alternator whine slighty in the speakers when car turned on. I thought it was bad ground but have tried several different ground locations which are all clean and sanded yet same results occur. All power cables are not near any vga or speaker wires.

is there a filter I can get to block out this type of noise? Anybody have any solutions or suggestions?

lbridges

There are probably filters you can use on the lines, but to address the problem directly, have you tried re-routing the lines in question. My advice would be to set them out (not under carpet, etc) and move the route they take around inside the car to see if you can get the noise to go away. Modern cars have all sorts of computer signal cables that can cause interference if you run a signal cable of your own near them.

HiJackZX1

I have the same issue.... I had it going through my speakers also..... If you have USB hubs, dont put them near the VGA cable, certain ones cause interferance. I bought filters for the amps and they work great, the brand was from install edge. It was the only brand that did not muffle sound and it boost the sound by 3 db. When it comes to the screen, I also have the flicker, and I also think its why my touch panel always unaligns its self. i have mine connected to the head unit power and ground, and everythin else to the M2-ATX.... i'll do some research and get back to you.

Alfredbra

thanx for you quick replies. The VGA cable I am using is a heavy duty one. Shielded and ferrite beads on each ends. Interference of an electronic object near the vga cabe is unlikely as when the car is off also there is no interference in the screen or speakers. If I disconnect everything and just leave the amp plugged in with no input I still suffer from alternator whine. obviously there is some interference comming from the alternator or the engine or something as it only happens as I said when the car is on. The flicker is more like wavy horizontal lines which scroll down the screen.

pokki

Have you upgraded your ground cable from batter to chassis and alternator to chassis?

Alfredbra

Can you explain a little why that would help much? As I said when the car is off the whole system is fine. only when the engine is running I get interference

Alfredbra

update. When I plug a laptop to the screen the noise on the screen is completely gone. and infact when the vga cable is unplugged when the screen says "disconnected" there is no noise either. and when i put the airconditioner on it gets even worse. I can only think of bad grounding but I have tried several ground points in the boot of the car yet all give me the same result. And if bad ground is the case wouldnt there be interferance when the car is off also? but I only get interference when the car is on......

pokki

Many cars are built cheap so they'll use the minimum thickness wire for every element. Adding a car stero + carputer creates a significant amount more current draw than the factory wiring was designed for.

As you "overload" the wiring you experience voltage drops. As the voltage drops your alternator works harder. I won't pretend to know why a stressed electrical system is more prone to noise, but it happens and I've solved many audiable wine issues through good grounding practises (that includes upgrades of major factory grounds) and is something I'd recomend to everyone getting a stero system installed practises.


Your boot groundings may well be fine (I presume your using suitable large cable, sanded back the paint and used a solid bolt point). It may well be your battery to chassis gorund or alternator to chassis gorud that the issue.


Poor grounding doesn't tend to be as noticeable with the car off as there are less electical devices operating, and there's no alternator running.

Alfredbra

I see, I will try this out. How would you upgrade the ground? attatch a thick 8gauge or so wire to the negative terminal to the body???

pokki

4 guage min from -ve batt to chassis/-ve alt to chassis. Crimped with good lugs, and bloted to the chassis where the paint has been sanded back.

RS3RS

That always drove me crazy, I don't think I ever totally eliminated mine

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HiJackZX1

me either RS3RS.....