PVM-2950 streaking problem

[wgs]

Over the past 2 years I collected quite a few CRT TVs and monitors, primarily Trinitrons. Some of which have this smearing effect. When a bright colored object "hits" a darker background it leaves a streak of a few cm to the right of the image. This is the can look unpleasant, especially when having bright moving objects on screen.
This is from my PVM 2950qm:


Notice the white tail the stars leave to the right.
In person it looks much worse.
What could cause this?
I have seen people having similar issues with their Trinitrons but no one had a solution. Recap did nothing in those cases.

My CRTs that have this problem:
Both of my PVM-2950QM, KX-2920QM, KV-14T1D, KV-25X5D

And my CRTs that don't have this problem:
PVM-2044Q, PVM-2730QM, BVM-2010P, BVM-20F1E, KV-E3431D, KV-D3431D, B&O MX8000, all of my VGA Monitors

[gray117]

Test: effect reduces with (a silly low) reduced contrast? (Not a fix just observation)

Almost certainly due to capacitors somewhere, maybe unit flyback.

However, I you might be able to also adjust to a more satisfactory level by tweaking down either colour drives or bias in service menu and balances with brightness contrast, and/or even via an adjustable pot inside, near neck which increases cathode ray power (too low and picture will just cut off)... Usually some combo of this can prevent need to recap for many years. But recap is likely only true fix.

Given the obscene amount of caps on a 2950 you'd probably try and live with settings tweak first, before then working on high power related caps.... And working out from there... Need to have a look at service manual for anything more specific than this

[wgs]

Hi, thanks for your response.

Yes, the effect reduces when lowering the contrast, but it wasn't set very high to begin with. I always keep the contrast as low as possible on my tubes.
Also I already tried playing around with R/B drive, Cut off etc. in the service menu. But to no avail.
I might try opening the monitor and change the G2 voltage.

As for recapping... Two of my other monitors have been recapped by a professional before I bought them but they still have this issue. But if nothing else helps, I might look into that.

[SuperSpongo]

Is this a 2 Chip SNES? Could you verify with another console?

EDIT: Oh you said you don't see the problem on the BVM-2010P and BVM-20F1E... okay, then this might not be the problem.

[wgs]

It's from a Wii running SNES9x. No matter the console or the cable used (all high quality RGC Scart cables), all the same result.

Edit: I also remember two Sony sets I sold some time ago, a KV-29X5D (had streaking) and KV-DX27TD (had no streaking). Seems to me that the really old monitors from around 1990 didn't suffer from this.

[SuperSpongo]

Yeah, it's a common problem for sure. I encountered it with many Bang & Olufsen sets (although I'm not 100 percent positive we're talking about the same thing).
I recently saw a video on this with new (to me) info. It's not directly applicable here but it shows that it's not always caps at fault:

https://www.youtube.com/watch?v=D_tlBUryNTo

[wgs]

I have 3 B&O sets, 2x MX8000 and MX4200 and none of them have it. Lucky me I guess.

Interesting video for sure. In my case the bright trails only go to the right instead of across the whole screen. Yeah, probing the neckboard with a multimeter for bad resistors might be worth a shot.

Interestingly, the ghosting does not occur on a completely black background. Only on darker grays, greens etc..

[SuperSpongo]

B&O televisions had a major electronical overhaul for the MX8000 and MX4200, it seems. These sets are not prone to bad horizontal linearity either.
I saw the effect on an MX5500, MX6000 and two MX7000 sets.

[wgs]

So I checked every resistor on the neckboard. All within spec. I also checked on my KX-2920QM and on my little KV-14T1D TV. All good. So I guess that's not the issue. :/

[Josh128]

I have 3 B&O sets, 2x MX8000 and MX4200 and none of them have it. Lucky me I guess.

Interesting video for sure. In my case the bright trails only go to the right instead of across the whole screen. Yeah, probing the neckboard with a multimeter for bad resistors might be worth a shot.

Interestingly, the ghosting does not occur on a completely black background. Only on darker grays, greens etc..

Sounds like some kind of cutoff problem, though I know you said you've played with cutoff in the SM. Something in the R/G/B drive circuit, for sure.

[danehenas]

Sorry if I'm a bit off subject, but I found you guys by Googling B&O Beovision MX8000. I have one in the garage that quit working with the rotating base. It's beautiful! I get the text prompts on the screen, but no other picture. Does anyone know someone who still works on these? I'm in Sacramento. I have opened it before and have pulled boards before and sent them off to be fixed. I had a local TV repair guy go through it and test and replace some caps--he knows what he's doing, but he gave up... he didn't charge me which was very nice. My wife is wanting me to dump it if I don't get it working--I don't want to do that....

Dane Henas
dane@danehenasdesign.com