JVC D Series Horizontal Smearing on the Composite Input

[old_tv_nut]

Interesting - The episode 1 VHS (IMG 7801) has a very noticeable negative smear. This could be a deliberate design in the VHS machine, intended to enhance contrast of mid-size details. Can you see this negative smear on other TVs?

I also wonder if the problem set does not have a proper 75 ohm video termination and/or one of your sources does not have a proper 75 ohm termination.

[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).

[Electronic M]

As I understand it none of the consumer video tape formats store video as composite. Luminance is FM modulated and color is either heterodyned and recorded directly or modulated onto a separate carrier.
The whole reason S-video exists is that if the separate y and c signals in the deck aren't combined it improves dubbing and display quality.

[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

[vol.2]

Originally Posted by Electronic M

As I understand it none of the consumer video tape formats store video as composite. Luminance is FM modulated and color is either heterodyned and recorded directly or modulated onto a separate carrier.

Oh that's right I forgot. It's stored kind of like color TV information is broadcast, more or less. But the color information is much lower quality than RF. Specifically because the color information is limited to 629kHz, and there are fewer lines of resolution.

So I guess it'd be better to use a SVHS machine, assuming it's spitting out the raw YC info from the VHS tape and not doing any weird combining and then splitting business.