minivan player - issue with ghosting on LCD screen

[macleod]

I was hoping someone would be able to recommend a fix for a ghosting issue that I am having with the LCD (5.6 audio<something>) display that I am having in my DVD player that is in my minivan.

I have done some research about EMI and have even put electrical tape around all of the rca connections to cut down on the ghosting effect. There doesnt seem to be a lot of information on this available on the internet.

Basically, I bought a mini DVD player (blaupunkt DVD-ME1)and then ran the line (which contains the power) up through the lining of the minvan and then dropped it into the LCD (Mobile Authority M58) screen. In the store at Fry's, the picture looked fantastic, however, in the van it looks horrible.

Unfortunately, I cannot replace the wire to the video and audio as it also has the power.

I plan on doing some additional troublshooting, but having the dvd player run power from an AC circuit (instead of the van's battery) and keeping everything else the same.

I dont remember that model of the dvd player (plan on entering that here when I get home).

Was hoping someone else has had a similiar problem and had found a solution to it.

[Alan69]

Ok first, electrical tape is vinyl. Shouldn't do a thing in the world for ghosting. It basically takes metal to have an effect on EMI.

You need to hook the whole thing up on the van's power but outside the van. You did test your units uninstalled before installing it didn't you? Likely a problem with one unit or the other.

If it is ghosting, it's a good but secondary image. Unlikely to be general interference from the van etc, because that'd make a more random noise. Usually it's a termination problem making signal reflections, which would be internal to the LCD or DVD player. But COULD be a very poorly shielded cable. Maybe even if the power carrying leads are all in with the video lead, it should really have the shielding around the video then the power leads outside the shield, even if still in the same plastic cable jacket.

If the units are ok and it's a poor quality cable and coming from the cable being near the vans metal or something else in the van it'd take metal shielding tape all along the cable to affect it. Then connect the shielding tape to the outside ground of the video connector to make it grounded.

There are a few other things to try, but I'd put my money on you setup not working outside the van any better than inside.. Try not on AC but on it's DC on the van's battery, just outside away from metal with van not running, then with van running to see if it's noise from the van. Standard troubleshoot, you have to use different configurations to figure out what is actually making the problem. Also make sure you're getting good power to the units, too small wiring can make a lot of problems appear. Shouldn't be the problem though if you hook up straight to battery with unit outside to test it out.

Alan

[BJ_M]

nice page on car emi filters http://mtifilters.com/mtifilters/EMIRF.html

the ghosting as mentioned is most often from the dvd player to the screen (poor quality cable -- use double shielded in a car and proper 75ohm connectors) .. but if its an all in one unit .. its something else .. if its running dia. (the ghosting) , it could even be a ground loop issue..

[macleod]

thanks for the information. I edited the message with the actual model info for the player and the LCD screen.

ps. the mini player plays EVERYTHING (except divx/avi). It is an awesome player to have in the vehicle for long trips. Also plays mp3, etc.

Back to the post.... again, thanks for the information. I guess "electrical tape" is just a clever name, . I am going to have to do some tests on it outside of the vehicle. My wife, however, doesnt want me farting with it because we are going to take a trip at some point in the future and she doesnt want me to break it. Whatever

what would be a "d-uh" way of testing the grounding issue? The player sits right below my chair (not physically conneccted to anything) and I have a tape to CD converter going from its output into our van tape player. Outside of that, it just connected "normally".

[grossjamesh]

I would suggest that a trip to a qualified auto electronic shop is in order.
Get the unit professionally installed.
I have to see a good homebrew installation of video equip in a car.

[macleod]

actually the player was professionally installed. The only thing I did after they hooked it up was run the cable up through the van to the LCD screen.

There wasnt any home brewin' happening with this one. I didnt want to spend $200 on something and then have me miss a wire. Actually, they told me that the installation book was wrong and had I followed the directions, I would have fried the thing.

When I have an opportunity to, I am going to hook up the player to AC and remove the whole thing from the van to see what I get. I am starting to lean towards the groundloop idea as the article that I read describes the picture I get pretty well. Anyone know of an acid test I can do on it to make sure it works (without blowing the damn thing up )

[BJ_M]

isolate everything from the van chasis and run it right from the battery ... now touch each piece to the chasis (a good ground point or run a cable from your battery NEG terminal) ..

if the picture goes wacky as before -- a ground loop ..


to get rid of it you will have to either isolate the mounting from your van body or use the van body as your ground and isolate the gorund in the cable or use an isolation transformer for video (might be tough on that custom cable) .. best to let a real pro installation handle it. make sure ground is less than .1 ohms .. and single point of ground (known as a star ground method) ... if the installers have a blank dumb stare when you ask the about ground loops or emi isolation -- go somewhere else quickly ..

either way can be danger if not done correctly as if not done correctly you could get a BIG freaking shock touching player/screen and touching a ground point in the van ..

[The village idiot]

If you have a secondary image of the disk that is playing, then the only things it could be is a hardware problem, or a cable problem! It could be that the "ghost" is mearly a significant delay between chroma and luminance. Typical of long runs of really cheap cable, or a damaged cable.

It is a car, ALL ground loops can be eliminated by attaching a wire from the device to the body (not plastic parts) of the car! The body of the car IS the return path (negative pole). Unless it has some special connector on the end, Go to Radio Shack, and get a video cable that will reach between the player and the display. Then you can see if that is your problem. If not, you will have to pull the equipment out of the car and find out what is wrong.

And if it was installed, why didn't they run the cable?

[BJ_M]

If you have a secondary image of the disk that is playing, then the only things it could be is a hardware problem, or a cable problem! It could be that the "ghost" is mearly a significant delay between chroma and luminance. Typical of long runs of really cheap cable, or a damaged cable.

It is a car, ALL ground loops can be eliminated by attaching a wire from the device to the body (not plastic parts) of the car! The body of the car IS the return path (negative pole). Unless it has some special connector on the end, Go to Radio Shack, and get a video cable that will reach between the player and the display. Then you can see if that is your problem. If not, you will have to pull the equipment out of the car and find out what is wrong.

And if it was installed, why didn't they run the cable?

the shield of the video cable and alos those special power cables they come with have a ground also .. thats three paths right there (the third is the mounting to the body in some cases) ..

[macleod]

And if it was installed, why didn't they run the cable?

because I am a cheap-ass

The hard install was $25 at fry's and for them to run 1 cable from the back of the player up through the minivan and down into the LCD screen was going to be another $50.00. Figured, cant be that hard since it is just cable.

On the ground loop thing, all I would need to do is touch the dvd box (chassis) and then touch a metal part on the van? Just want to make sure that I dont need to touch something in particular on the player.

Think I'll hit radio shack on the way home. From looking at the cable, it obviously the cheap stuff. Think I'll see what they can do for me as a replacement cable and see what that does. Worst case is I can just return it to them

I was getting scared with what BJ_M was saying where I need to let a professional do this. I cant mess it up (partly because the rig cost me $200 and mostly because my wife will kick my butt).

I think I'm gonna try out the rca wires and stuff first and see if that is it and then move on (need to get new wires anyway).

Thanks all for your input. I was amazed that I could not find information on the net about this. This info will help a lot of people out (I am SURE that at least one other person has had this problem before). Course, that is if they use the search function.

[The village idiot]

It is very difficult to make a ground loop in a car. If the chassis of the equipment in mounted properly, i.e. mounted to the metal, then you should be all set. Ground loops don't normally show up as a second image either, at least not without a rolling bar on the display. The number of return paths is of no concern unless they are all isolated from each other. How many cheap consumer electronics can you find with isolated grounds on every connection? You would be lucky if the video has a different ground from the audio, and normally they all attach directly to the chassis, along with power ground if it has a 3 conductor power cable. And for DC power, power really should attach directly to the chassis to help eliminate ignition EMI. The only part that creates AC power is the display backlight.

It is also much more difficult to make a real ground "loop" in a car because you are dealing with DC power. There are no different phase to be concerned with. A ground potential difference should only raise or lower the DC potenial on the ground. You might see this as the picture becoming washed out, or too dark.

Unless someone put a screw that was too long into one of the pieces and it is shorting something out.

[BJ_M]

seen grounding problems only on dvd players with remote screens .. ive fixed 2 myself for people (isolated the screen from the chasis) - fixed it right up ... yes a GL ussually shows as rolling but in a DC power source its a dia. lines for some reason (same as our crt cube displays also) ..

dosnt mater if DC or AC - you can have a potential differance because of different resistance of the ground points ..

yes -- its rare , but he does have a problem and just offering some solutions .. as said at the begining its more likely due to cheap cables in a high rf/emi location ..

a short (in cable or mounting) is a good point .. running a cable through a car can strip insulation if you try to pull it in some locations sometimes ..

yea -- , ive seen the 2"+ screw installation method also -- even in home installs (ussually right into the crossover) ...

[The village idiot]

Never seen a ground loop make diagonal lines. Must be letting RFI into the system on the ground.

[Cornucopia]

I would lean toward checking the termination and the cable quality to minimize rf/em reflections along the path of what seems to be a LONG cord.

Isn't it possible at all to connect the power only and supply a separate path/cable for the video? Maybe with an extender/adapter? Man, Radio-TV-Film 101 class plainly said don't run your power cable parallel to or even NEAR your signal cable, unless you don't care about interference.

HTH,
Scott

[BJ_M]

I would lean toward checking the termination and the cable quality to minimize rf/em reflections along the path of what seems to be a LONG cord.

Isn't it possible at all to connect the power only and supply a separate path/cable for the video? Maybe with an extender/adapter? Man, Radio-TV-Film 101 class plainly said don't run your power cable parallel to or even NEAR your signal cable, unless you don't care about interference.

HTH,
Scott

not to much a problem with DC power ... many security cameras in fact multiplex the power right on the video cable ..

[Cornucopia]

DC. Of course, what was I thinking...

[macleod]

last evening I was fiddling with the audio and video cables and when I moved the cables the picture jumped around a little.

What I am going to do at this point is run an extension cord out to the van and plug it into the DVD player with car on and off and see what it does/doesnt do.

If the issue clears itself up, can I assume then that it would have something to do with the DC converter and/or the ground looping issue. I shudder to bring this up now since there is always one piece of information that someone doesn't give out because "they" think it isnt going to have an effect on anything, but I have never bolted the dvd player to the van. It simply rests under my seat.

Now I am almost thinking that I have caused my own problem (find out more tonight) by being a cheap ass on the "installation".

If y'all think that is what it is, PLEASE flame away. I deserve it

[macleod]

Well, to close the book on the issue, I did some more testing on the unit.

I used the AC power and turned everything else off and it looked the same.

I looked at my audio cables (composite) and started farting around with them and saw the picture jump around (the audio cables looked like they were 20 feet long). I replaced them with some 6 inch audio cables and then reseated the vdeio composite cable and fired her up. PERFECT picture. I then switched back to DC and would rate that picture a 9.5 out of 10 (10 being the picture quality of the AC test).

So, after all of this, it turned out the audio cables, in some way, were the cause of my problem. To give you an idea of the picture quality before, it was almost unwatchable during the daytime and it night the ghosting was ridiculous. Now, it has a clear crisp picture. Wahoo.

Thanks again for everyone's input. Now, hopefully, if the rest of the forum knows how to use the search, they can find this information

[The village idiot]

Now, hopefully, if the rest of the forum knows how to use the search, they can find this information

Now that is asking a lot