Beovision avant 32 screen streaks

7 replies
C(
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capstan (archived)
Bronze
Posted December 15, 2011 at 08:36 GMT
#1943873

Hi, the anti-reflection coating on the picture tube of my BV Avant 32 (2003/4 vintage) has annoying vertical purplish/rainbow streaks, probably caused by someone cleaning it with the wrong type of cleaner.

 

They are only visible in a dark room when a light shines onto the screen, or against dark images when the set is switched on. They are distracting, and I’d like them gone.

 

Has anyone any experience of how to remove them? I’ve tried most things to no avail, and it seems the only option left is to remove the plastic AR coating. If so, is it an easy job, is a razor blade the best kind of tool? Can the coat be left off (it’s an optional extra on the identical BV3-32 tube, so I guess so), or does it create an inferior picture?

 

Alternatively, can a dealer/technician fit a new AR coat.

 

Any comments gratefully received.

K(
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kokomo (archived)
Bronze
Posted December 15, 2011 at 09:46 GMT
#1943874

Hi and welcome to Beoworld.

Your idea of you removing the AR coating frightens the hell out of me, I don't know what others think, but IMO I'd put that out of your mind straight away. Razor blade!!!!

On the AR screen of my Beovision 3 I get the same purplish effect when I apply glass cleaner and clean the screen. I found it not a simple wipe over and the streaks were gone, but it required a little more polishing effort with suitable cloths (not hard!). First time I attempted a clean the visual streaking horrified me and I thought I'd done some permanent harm. A bit more work though and they disappeared.

Point I'm trying to make is don't assume that the streaks you describe indicate some form of damage (although of course they may be!).

You don't say what methods you've tried so apologies if you tried everthing possible.

Others on this forum are far more knowledgable than me concerning the properties of the AR screens and I'm sure they'll add their expertise.  

C(
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capstan (archived)
Bronze
Posted December 15, 2011 at 16:02 GMT
#1943875

Hi, and many thanks for the quick reply.

Sorry if I frightened you with my razor suggestion!

But I have tried with mild metal polish, and even oven cleaner, but rest assured these were all in small corners, and with extreme care and lightness of touch. However, all have proved ineffective. And they've also done no damage.

I’ve also tried glass cleaner, liberally applied on a soft old t-shirt, but to no effect either.

I’m beginning to wonder if the streaks are on the inside of the AR film, or are something to do with adhesive deteriorating. Is this possible?

I also wonder if this film can be removed (with or without a 'blade)  since it was originally an option on the BV3. Alternatively, maybe it’s available as a BV part.

Maybe the coating was really only an advantage if you live in a sunny place where the rooms are often full of light reflections, hence it was optionally offered on some models. As I'm in the frozen north of the UK, maybe it wouldn't really be needed!

In some other forums there are several threads on this topic, re. other makes of  TV, and especially computer screens, where it seems to be a common issue which most folk resolve with a sharp knife/razor blade and a surgeon’s touch. Hence my query.

However, any further views would be appreciated, as the streaks are a distracting.

 

 

 

JL
Offline
jldmelb
Bronze
Posted December 15, 2011 at 18:04 GMT
#1943876

I wear glasses, and I find the best thing to clean my TV screen is with the cleaning cloths that come with glasses. No need to spray anything on, they work just as they are. For the more difficult parts, I wet a tissue and remove the stubborn parts, then redo with the glasses cleaning cloth.

All glass components benefit from this method. Beocenter 9500s look like new, Master Control Panels look amazing again!

K(
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kokomo (archived)
Bronze
Posted December 16, 2011 at 06:58 GMT
#1943877

"But I have tried with mild metal polish, and even oven cleaner, but rest assured these were all in small corners, and with extreme care and lightness of touch. However, all have proved ineffective. And they've also done no damage."

 

Hi again Jonathan. Razor blades and now metal polish!! Seriously, from what I've read on this forum in previous posts, the AR is a sprayed on or an other ways applied finish to both sides of the screen. It could be that the back of the screen is where the streaks are so it might be worth removing your screen to see.

To be honest I replaced my non-AR screen with an AR one some years back and I'm not convinced it made that much of a difference but what little it did is better than nothing. 

TO
Offline
tournedos
Bronze
Posted December 16, 2011 at 07:09 GMT
#1943878

There are probably several kinds of AR coating methods used, but whatever it is, I'm sure it's impossible to reapply. Once it's gone it's gone, and if you can't get it off completely, the result will look horrible. Therefore you should make sure that what you see really is a problem and not the way it normally looks - on the MX/LX series I have, the coating shows up as purplish hue in some conditions (but never bothers me).

I'm not convinced on the actual anti-reflection benefits, but with AR the sets look better when turned off. The bare tube is always somewhat gray, not black.

The front glass for Avants may well be still available as a spare part, but frankly I believe you could buy an entire non-functional Avant for less to swap the glass if need be.

C(
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capstan (archived)
Bronze
Posted December 16, 2011 at 07:48 GMT
#1943879

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Hi again, thanks for everyone’s help with this.

 

Just to be clear about the issue, the streaks are on the AR. This is a polyurethane (or similar) film, a very fine one which you could easily think wasn’t there unless you look very closely around the edges of the screen. It’s not a spray-on finish or anything similar, tho’ I understand some other manufacturers preferred to use a spray coat to get a similar effect.

 

The film is stuck on the front of the glass plate. The plate is mounted on front of the tube and covers the matrix.

 

The AR film is accessed by removing the dark contrast screen on the outside of the set (secured by 2 bolts underneath the screen – slacken them and just lift n pull gently towards you). My contrast screen is fine. The picture itself is fine. But the film is not.

 

If it can't be peeled off (by starting in a corner with said razor blade), then swapping the glass picture screen on the front of the tube is one idea, but it looks as if this would be a major job to remove, and not one I would ever attempt (gas, elec, and vacuum to deal with, and possibly more I guess). It would surely mean replacing the whole tube, would it not?

 

So, we’re left with either peeling it off (and maybe replacing it, if possible) or removing the streaks, but what with?

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