Question about CRT picture tube - UK Vintage Radio Repair and Restoration Discussion Forum

Retro-valve-guy · 2nd Feb 2017, 9:57 pm

Okay so this is a Grudnig Zauberspiegel 53T has about 17 tubes in it and i have a question about the crt itself, never camed acroos one that had a theme like this one, kind of a weird color picture tube and was wondering if its normal being like that

http://www.radiomuseum.org/r/grundig...53_luxust.html

So does the picture tube look fine ?, Im just worried that the weird color could be the result of air that leaked into it ??

And the guy wants 100 euro for it,I know its a risk for that money buying it without being able to test the picture tube,but can maybe inspect the insides,
I offered 50 euro and havent heard back fro him yet

so ?

Radio Wrangler · 2nd Feb 2017, 10:16 pm

Some tubes had implosion guards bonded onto the front with an optically transparent adhesive. Some camera lenses have elements bonded together this way too. The adhesive can go off and suffer fungal infestation. This has that sort of appearance.

Some tubes were coloured to enhance contrast, but I don't think an uneven colour would have helped sales.

David

Retro-valve-guy · 2nd Feb 2017, 10:37 pm

The picture tube itself looks fine ? its only on the outside ? can that fungal infestation affect the picture, is it like Cataract on a color tube ?

Can it be cleaned

Also what do you mean by unevean color ?*?

Heatercathodeshort · 2nd Feb 2017, 10:49 pm

There is a possibility that the inside of the Perspex implosion screen is just very dirty.
I don't think they produced 'bonded tubes' in the 17" size. Maybe the whole cabinet was dirty and the guy cleaned it for sale leaving the cigarette smoked screen alone being inaccessible to him.

Nothing is guaranteed unless you remove the back and have a look. It certainly is a strange colour but I have seen similar where a whole family smoke. John.

2nd Feb 2017, 9:57 pm	#1
Retro-valve-guy Retired Dormant Member Join Date: Aug 2013 Location: Celje, Slovenia. Posts: 128	Question about CRT picture tube Okay so this is a Grudnig Zauberspiegel 53T has about 17 tubes in it and i have a question about the crt itself, never camed acroos one that had a theme like this one, kind of a weird color picture tube and was wondering if its normal being like that http://www.radiomuseum.org/r/grundig...53_luxust.html So does the picture tube look fine ?, Im just worried that the weird color could be the result of air that leaked into it ?? And the guy wants 100 euro for it,I know its a risk for that money buying it without being able to test the picture tube,but can maybe inspect the insides, I offered 50 euro and havent heard back fro him yet so ? Attached Thumbnails

2nd Feb 2017, 10:16 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,901	Re: Question about CRT picture tube Some tubes had implosion guards bonded onto the front with an optically transparent adhesive. Some camera lenses have elements bonded together this way too. The adhesive can go off and suffer fungal infestation. This has that sort of appearance. Some tubes were coloured to enhance contrast, but I don't think an uneven colour would have helped sales. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

2nd Feb 2017, 10:37 pm	#3
Retro-valve-guy Retired Dormant Member Join Date: Aug 2013 Location: Celje, Slovenia. Posts: 128	Re: Question about CRT picture tube The picture tube itself looks fine ? its only on the outside ? can that fungal infestation affect the picture, is it like Cataract on a color tube ? Can it be cleaned Also what do you mean by unevean color ?*?

2nd Feb 2017, 10:49 pm	#4
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Question about CRT picture tube There is a possibility that the inside of the Perspex implosion screen is just very dirty. I don't think they produced 'bonded tubes' in the 17" size. Maybe the whole cabinet was dirty and the guy cleaned it for sale leaving the cigarette smoked screen alone being inaccessible to him. Nothing is guaranteed unless you remove the back and have a look. It certainly is a strange colour but I have seen similar where a whole family smoke. John.