JVC D Series Horizontal Smearing on the Composite Input

[vol.2]

Originally Posted by BenM86

As far as the settings go, it's possible it's been messed with. D series TV's tend to trade hands often, so im sure the service menu has been accessed. The red push was already disabled when I got it, so someone has been in there at least once. I should at least sit down and make sure everything is set to factory based on the service manual just in case.

I did have that thought. If you can do it safely, it's a good idea to make sure everything is correct. I wouldn't change any settings that aren't explicitly called out and explained in the service menu though; in my experience, many service menus contain options that are not documented for various reasons, and they shouldn't be messed with. Sometimes it has to do with some very basic operations that would never need to be changed, and sometimes they adjust things that weren't implemented in the circuit design (optional inputs and features).

There are absolutely settings in some service menus that will remove the picture, including the service menu text itself. If that happens, you're kind of screwed.

Again, I don't know JVC stuff too well, but I've run into it in other sets.

Recapping could help, but I'd recommend getting a good LCR meter (or an ESR meter if you want to save some money) and actually checking the caps you pull out rather than doing a shotgun. Sometimes shotgunning a set will end you up in worse shape than you started. This usually happens as a result of making mistakes (pulling up pads and traces, putting in caps backwards), but it can also happen because of less obvious mistakes such as using the wrong type of cap.

And that's why checking voltages is the way to go, because it points you to an issue in the operation of the circuit at a certain point. Once you discover a wrong voltage, you can scour the parts that would effect it and that should lead you to a problem. Sometimes there are multiple independent problems, or many problems caused by a cascade failure.

Whatever you're looking for seems like it's pretty specific though, because it's only on one input. Either the settings are wrong, or something touching only that input signal path is wrong. I like those chances.

But yeah, make sure the settings are correct first.

[BenM86]

Originally Posted by vol.2

I did have that thought. If you can do it safely, it's a good idea to make sure everything is correct. I wouldn't change any settings that aren't explicitly called out and explained in the service menu though; in my experience, many service menus contain options that are not documented for various reasons, and they shouldn't be messed with. Sometimes it has to do with some very basic operations that would never need to be changed, and sometimes they adjust things that weren't implemented in the circuit design (optional inputs and features).

There are absolutely settings in some service menus that will remove the picture, including the service menu text itself. If that happens, you're kind of screwed.

Again, I don't know JVC stuff too well, but I've run into it in other sets.

Recapping could help, but I'd recommend getting a good LCR meter (or an ESR meter if you want to save some money) and actually checking the caps you pull out rather than doing a shotgun. Sometimes shotgunning a set will end you up in worse shape than you started. This usually happens as a result of making mistakes (pulling up pads and traces, putting in caps backwards), but it can also happen because of less obvious mistakes such as using the wrong type of cap.

And that's why checking voltages is the way to go, because it points you to an issue in the operation of the circuit at a certain point. Once you discover a wrong voltage, you can scour the parts that would effect it and that should lead you to a problem. Sometimes there are multiple independent problems, or many problems caused by a cascade failure.

Whatever you're looking for seems like it's pretty specific though, because it's only on one input. Either the settings are wrong, or something touching only that input signal path is wrong. I like those chances.

But yeah, make sure the settings are correct first.

Well, the plot thickens. I have no idea why I didn't try this before. I went ahead and plugged the DVD player into the composite input which I had never done before, aaaand, its fine. So I guess there's nothing hardware wrong on the TV. I still dont understand why the issue is happening though.

Id be willing to believe the VCR and laserdisc are both just worn out, but then why don't they have the same artifacting on my other TV's? ill attach two comparison shots one with the episode 1 vhs and one with the episode 2 dvd. The vhs should of course be worse, but not THAT much worse. Same input, same settings on the TV and camera. And again, the VCR does not look this bad plugged into any of my hdtvs, just this one. Somehow im even more confused than I was before lol.

[vol.2]

Originally Posted by BenM86

Id be willing to believe the VCR and laserdisc are both just worn out, but then why don't they have the same artifacting on my other TV's?

It could be that the "HDTVs" simply have a greater tolerance for noise or excessive voltage in the signal.

Your VCR and Laserdisc players could be worn out, and the JVC could also have some weak components, and it's only when two weakened devices are combined that you see the greatest issues in the raster.

The DVD player is a newer device with a much cleaner signal.

Either way, you shouldn't be seeing all that smearing and ghosting, and there's either something wrong with both the Laserdisc player and the VCR, there's something wrong with the TV, or both.

[Alex KL-1]

Ohh, the sources... definitively.
I have a chinese S-Video VGA to NTSC that have some smearing only using with older TV's and this not appears with my more "recent" 29" TV using a jungle IC like that ("all-in-one"), aka, resolution is fine with the 29", and smeared with the olders. Then I put a DVD for testing all it's inputs and with the DVD all TV's have good fine resolution***. Is a bit odd since the 29" TV have a good/very definite and fine video resolution (I think it will not hide the aforementioned issue). Odd to explain that.

***some are better than others but all can show the chinese converter issue...

[BenM86]

Originally Posted by vol.2

It could be that the "HDTVs" simply have a greater tolerance for noise or excessive voltage in the signal.

Your VCR and Laserdisc players could be worn out, and the JVC could also have some weak components, and it's only when two weakened devices are combined that you see the greatest issues in the raster.

The DVD player is a newer device with a much cleaner signal.

Either way, you shouldn't be seeing all that smearing and ghosting, and there's either something wrong with both the Laserdisc player and the VCR, there's something wrong with the TV, or both.

Just thought I would post an update. I finally got a chance to try a different VCR. It’s an older model from 1984 that I just refurbished with new belts and what not, and it has the exact same issue on this crt, just slightly worse. Both VCR’s also do the same thing on RCA and RF. I’ve also noticed that while it does smear in laserdiscs, it’s not nearly as bad as it does on the VCR. But again nothing from video game sources like my snes or from newer video sources like a DVD player.

Pretty much given up at this point, outside of a full tear down and recap of the TV I doubt it’s something that’s really fixable. Next step is to find an SVHS player and see if the TV likes the svideo signal any better I suppose lol.

[vol.2]

Originally Posted by BenM86

Just thought I would post an update. I finally got a chance to try a different VCR. It’s an older model from 1984 that I just refurbished with new belts and what not, and it has the exact same issue on this crt, just slightly worse. Both VCR’s also do the same thing on RCA and RF. I’ve also noticed that while it does smear in laserdiscs, it’s not nearly as bad as it does on the VCR. But again nothing from video game sources like my snes or from newer video sources like a DVD player.

Pretty much given up at this point, outside of a full tear down and recap of the TV I doubt it’s something that’s really fixable. Next step is to find an SVHS player and see if the TV likes the svideo signal any better I suppose lol.

That would be interesting, but IIRC, SVHS can't get real s-video out of a VHS tape because VHS actually stores the video as composite. Any of the composite artifacts that are there in the tape to begin with are going to be there anyway. So basically, if you see an improvement, that would suggest that the s-video input on the TV has a cleaner signal path, or that it's the VCRs you were using that are both (all) somehow outputting a dirty signal.

Conversely, if the image still looks bad, that won't really tell you much unless you can get an actual SVHS tape recorded as a real SVHS tape from a high quality source. This is also assuming the player is in good condition and doesn't have a bunch of failing SMD caps in it (as so many of them now do).

[BenM86]

Originally Posted by vol.2

That would be interesting, but IIRC, SVHS can't get real s-video out of a VHS tape because VHS actually stores the video as composite. Any of the composite artifacts that are there in the tape to begin with are going to be there anyway. So basically, if you see an improvement, that would suggest that the s-video input on the TV has a cleaner signal path, or that it's the VCRs you were using that are both (all) somehow outputting a dirty signal.

Conversely, if the image still looks bad, that won't really tell you much unless you can get an actual SVHS tape recorded as a real SVHS tape from a high quality source. This is also assuming the player is in good condition and doesn't have a bunch of failing SMD caps in it (as so many of them now do).

Decided to try something a little different. Ordered a used Kramer composite to svideo decoder on ebay for cheap. Basically an external comb filter. At the very least for $20 it will simplify my input chain. But since it is a digital comb filter and outputs its own signal my hope is it will sidestep whatever is causing the smearing. We shall see, fingers crossed