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-   -   Worse colors with NR on NV-FS88 and NV-FS1000? (https://www.digitalfaq.com/forum/vcr-repair/13957-worse-colors-nr.html)

IfyL 12-25-2023 08:58 PM

Worse colors with NR on NV-FS88 and NV-FS1000?
 
6 Attachment(s)
I'm wondering are the colors supposed to be worse with NR on, or is there a problem somewhere?
At least on FS88 you can turn on edit mode to fix the problem.

latreche34 12-25-2023 10:41 PM

Your tape is miss tracking at the top frame, So it adds noise.

IfyL 12-25-2023 10:57 PM

I'm not talking about the noise, saying the colors just look worse with NR on, or EDIT turned off.
And tape isn't mistracking, the vcr just has a bit of noise on pause.

aramkolt 12-26-2023 12:12 PM

Looks to be lots of "chroma noise" there. I believe in a lot of cases that implicates the TBC circuitry needing a recap and that also probably is why the colors are worse passing through it. I've got some full frame TBCs with chroma noise reduction features and would be interesting to see what that would do to that.

Not sure if it's possible to reduce chroma noise like that and effectively adjust color in post?

themaster1 12-26-2023 01:36 PM

Have you recorder a belle nuit test chart to make sure ? or an smpte

IfyL 12-26-2023 06:53 PM

1 Attachment(s)
@aramkolt
As I said those are stills from a paused tape, which adds a little more noise which doesn't happen as much in playback.
And there's no TBC on the NV-FS88, but turning on the TBC on NV-FS1000 made the colors even worse. Maybe some other caps need replacement or something?

@themaster1
Interestingly, the test chart doesn't have major color shifting. It's only more present with skin tones and nature greenery videos.
Here in the sample I switch between all 3 modes, 1.Edit ON; 2.Edit OFF; 3.Noise Filter.
Hope this is good enough. I don't have any other type of test cards on the tape and can't record anything new on to it anymore.

aramkolt 12-26-2023 08:29 PM

Is the test chart recorded on to a VHS tape, or is that some sort of passthrough?

Since it doesn't show up with the test chart, almost makes me think it is the tape itself that has degradation (assuming the test chart was either more recently recorded) and/or is on a different tape than your other samples?

IfyL 12-26-2023 09:03 PM

It's recorded on to the tape right after the samples from my first comment. It's just a testing tape I recorded random stuff on to not that long ago, and everything was recorded to it the same day.

The color problem can occur on any tape, from movies to home recordings, so it isn't just one tape's fault, sadly. And no matter how well or good the tapes were stored, the problem still occurs when the EDIT mode isn't set to ON.

It isn't a huge deal, as the edit mode looks good anyway, but sometimes when a video is oversharpened, it'd be better to capture it without any more added sharpness, but I can live with it. Just wanted to know why that occurs.

hodgey 12-27-2023 08:01 AM

I've seen this on the NV-HS1000 at least, where the chroma looks a bit washed if it's not in edit mode. It's possible it's due to the trimpot chroma NR needing to be adjusted and/or the surface capacitors on the chroma module degrading but fixing either would be quite difficult. The capacitors sit on the underside of these hybrid ICs which you would need to desolder to access which would be a huge pain and probably a bit risky and at least on some of them also have some black coating on them. The trimpots to adjust the chroma NR gain and phase are also not very accessible and were meant to be adjusted with the board connected by connecting the boards via extension cables originally (which are going to be unobtainium these days) so it's virtually impossible to do nowadays as you can't really get to them while the board is plugged in normally and you kinda need to to observe the output on a scope.

I'm not sure if the same is true on the NV-FS88 and FS200 but it might.

Not that the analog chroma NR on PAL VCRs is super effective in any case in my experience though at least on these two models it doesn't cause the chroma to be shifted vertically afaik unlike on some other pal vcrs with analog chroma NR.

EDIT mode isn't technically adding more sharpness, it's actually softening/EQing and blurring less instead as it's skipping some filtering steps, though it can be a bit overly sharp/ringy in some cases. depending on the tape

IfyL 12-27-2023 07:44 PM

Very interesting explanation, thanks, but yeah, it seems very complicated. Maybe if I had the tools and a spare vcr I'd try it.
Hopefully the edit mode doesn't break too, which'd be a big shame.


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