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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 6th Oct 2022, 4:56 pm   #41
simpsons
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Default Re: Sony KV-A2942U very soft focus in middle of screen

Hi Marcel

Thank you for the update.

I wonder, given the technical improvements made for both colour cameras and televisions, following the NTSC standard in 1953 being approved for 525 lines, if the subject of colour TV developments wouldn't make an excellent article for the BVWS magazine.

When one thinks that it was only 15 years earlier that the BBC started the first high definition standard regular public broadcast on 405 lines with the technology available at the time..

I'm not technically competent to contribute having really only the articles in Television and the earlier Practical Television, plus others to call upon.

However, there are many contributors to this site who would be ideal?


Chris
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Old 6th Oct 2022, 8:49 pm   #42
Maarten
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Default Re: Sony KV-A2942U very soft focus in middle of screen

Quote:
Originally Posted by Heatercathodeshort View Post
I had numbers of Sony receivers that had received a heavy bump that caused mainly rainbow mis convergence and focus problems.
I think the very heavy weight of the large screen models lead to them being dropped by their owners. The 27" models were heavy but nothing like the 29" ones that almost without exception had flat tubes. I could never work out why the 29" ones were so heavy other than very thick glass. J.
The frame of the wire mask is particularly heavy.

I've seen the rainbow and misconvergence errors from sets that were dropped. Never knew about focus problems.
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Old 6th Oct 2022, 8:52 pm   #43
Maarten
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Default Re: Sony KV-A2942U very soft focus in middle of screen

Quote:
Originally Posted by simpsons View Post
In many ways the limiting factor was the broadcast system. Whilst DVD and later Blue Ray made a vast difference, squeezing extra information out of a system designed for 4:3 picture ratio then stretched to 16:9 was a tough nut to crack.

Chris
In my (limited) experience, in higher res computer monitors, the wire mask was the limiting factor.
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Old 6th Oct 2022, 8:55 pm   #44
Maarten
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Default Re: Sony KV-A2942U very soft focus in middle of screen

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Originally Posted by Retrorepair View Post
Trinitrons of course always had more glass than other sets but earlier models usually had metal cages also which didn't help matters.
Early shadow mask tubes also had cages around them. Later integrated into the tube, probably the same with Trinitron. I think most of the metal weight is the tension frame for the wire mask (aperture grille).
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Old 8th Oct 2022, 12:21 am   #45
Retrorepair
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Default Re: Sony KV-A2942U very soft focus in middle of screen

Just to slightly derail my own topic, I've noticed some pretty heavy blooming on this TV. I wouldn't expect this on a Trinitron of this era, at least to this extent.

https://youtu.be/TWft0C2t-E4

It's effect isn't as apparent in the video as it is in real life, this is far less than when a white screen is flickering (basically a blurry chaotic mess).

Is this something I should be blaming the flyback for? Are AE2 chassis really this bad? My AE1 set doesn't bloom like this.
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