Bleeding reds on a CRT

[LEGENOARYNINLIA]

Hey,

Bleeding reds on a cathode ray tube... I know this is a common problem as my old CRT TV which had remarkably nice picture quality also had this, but this time I have a professional S-video monitor in my hands and I want to do something about it. I've accessed the service menu and I've tried adjusting the cutoff for red, but it does not affect the bleeding effect. Is there anything I can do about this? Sometimes when I see solid blue on a dark background it is also somewhat blurry, but not as bad as reds overall.

The monitor in question is a JVC TM-1700PN.

Thanks!

[Ed Oscuro]

I found something for a consumer JVC set here, perhaps it's of use in hinting at their nomenclature for the service mode settings, though it seems like you don't need it:

Bottom Line:
I have now learned how to fix red push for all inputs by adjusting settings in the service menu.
1. Select the Video 1 Input (composite)
2. Enter the service menu as described below and select Picture mode.
3. Adjust the #36 R Y GAIN to 000.
4. Adjust the #40 CD MATRIX to 000.
5. Exit the service menu.
6. Select the Video 2 Input (Component Input).
7. Enter the Service menu again and select Picture mode.
8. Adjust the #37 CMP R Y GAIN to 000.
9. Adjust the #41 CMP CD MATRIX to 000.

This will fix red push for all inputs.

So there might need to be two settings to alter - R Y Gain and CD Matrix.

No luck finding a service manual, though I didn't try every hit exhaustively. There are plenty of sites offering it for sale though. To be honest, I am surprised any pro monitor such as this would have a red push (but then again, Y-C and composite in a pro monitor is also new to me). Sure it's not a problem with the source or input?

[LEGENOARYNINLIA]

Thanks for your input. I actually already have the service manual for this monitor, and I've been fiddling with the settings for a bit, but so far nothing has affected the bleeding. Also, I've tried four different sources so far and the results are the same.

[niall]

Convergence? Are you able to post a few pics of the issue?

[Fudoh]

how strong is the bleeding ? After all bleeding on highly saturated colors (especially reds) is what differentiates s-video (with a combined chroma carrier channel) from RGB with three dedicated color carriers. So - to some degree - this should be expected from a s-video signal.

[BazookaBen]

Sounds like a convergence issue. This can usually be mitigated in the service menu. Lots of info on the web on how to do that.

http://en.wikipedia.org/wiki/Cathode_ra ... color_CRTs

[LEGENOARYNINLIA]

Here are some photos as requested. All games are running on a PS2 through S-video using an official Sony cable.

Test grid from Capcom Generation 3 (240p): http://i.imgur.com/Qs2sefh.jpg

Shot from Capcom Generation 3 (240p): http://i.imgur.com/CEETOzq.jpg

Shot from KOF Orochi Hen (480i): http://i.imgur.com/rawOU7E.jpg

Shot 1 from KOF'94 Re-Bout (480i): http://i.imgur.com/fUP4EFG.jpg

Shot 2 from KOF'94 Re-Bout (480i): http://i.imgur.com/8MkW1PH.jpg

I also have a 14" PVM that does not have such issues when using the same S-video cable and same source.

I would be happy if I could ease the bleeding even just a little bit as I quite like the soft yet solid look this monitor has.

[gray117]

hmm might just be symptomatic of pvm doing a better job with the svideo than the jvc...

Is not a typical convergence issue, might be some kind of purity issue (would mean fiddling with the neck rings). However I wouldn't jump straight to that (especially if its just svideo and/or a particular device), because it's probably an outside chance...

... Don't suppose you've tried a couple of other devices and/or input combinations? Do they all exhibit the same behaviour to the same extent?

If there's nothing gained for adjusting red gain [there's not a separate option per input or something?] There may be something you could adjust an overall balance/gain - possible sacrificing some contrast to reduce the bleed. Again if nothing obvious via menu's you'll probably be looking at possible internal pots... and, again, probably not something you want to try tweaking as anything other than a last resort...

[fagin]

I'm with Fudoh.... it's probably a SVHS issue. Try an RGB source to see if the problem is reduced..... if it's not, it's a RED drive issue.

[LEGENOARYNINLIA]

This monitor has no RGB inputs.

Also, there are no pots to adjust inside.

[fagin]

But the TV has component input doesn't it?

[LEGENOARYNINLIA]

...what TV?

[fagin]

Apologies.... looks like I have brain bleed. I read the second post with the link. Put 2 & 2 together and came up with 9.56.

Since you don't have any other adjustments, you'll either have to like it or lump it I'm afraid.

Personally I'd probably try putting some resistance across the channels to see if it helps..... which it probably wouldn't.

[ninn]

Can I please see a color bars test screen?
maybe your contrast is just too high?

[fagin]

One of the screen shots show a colour bar.

[niall]

It's hard to diagnose without close ups of test patterns, but it looks like excessive Red drive to me - check the neck board to see if there are any pots or dials, or service menu for R drive-cutoff. Otherwise you're pretty much stuck if s-video is your only input.

[Endymion]

Looks like it could be convergence, but being so slight it could as easily be an inherent s-video situation, doesn't look terrible from the stills.

I'd either learn to love it or live without it, move on while you can still get another CRT that isn't knocked about. With RGB.

[LEGENOARYNINLIA]

After tweaking the service menu settings a bit more I got this: http://i.imgur.com/fwkduKL.jpg

I'm now done and satisfied enough with the results.

[fagin]

So you either altered the contrast or gain?