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Discussion Starter #1
I'm having a problem with my RP CRT HDTV. I've noticed that my picture seems "soft" especially when I'm looking at a zoomed out view during a sporting event. The close ups still look HD to me, but the zoomed out views just don't look crisp at all. I recorded HDNETs 10 minute HD test patterns, and it does seem to show I am only getting 600-700 lines of resolution as opposed to 1080. What are the things I can check to see if there is a configuration problem with my tv? Here is what I've tried so far:


Manual and electronic focus of the lenses

100 point convergence


Anything else??


Thanks!
 

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Discussion Starter #3
Ah, one thing I forgot... I did that a month ago for the first time in three years... same time I focused the lenses
 

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You verfied in the past in actually resolved 1080 lines?


Most of the CRT RP's even the best ones only like 960 or so , many way way less.
 

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Discussion Starter #5

Quote:
Originally Posted by JOHNnDENVER /forum/post/12859966


You verfied in the past in actually resolved 1080 lines?


Most of the CRT RP's even the best ones only like 960 or so , many way way less.

I can only verify qualitatively... I don't remember ever verifying the number, I just know my picture was much sharper at one time.
 

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I think one or more of your CRT's is wearing out from the descriptions.


Hard to say. The other thing that happens over time in CRT RP is the power supply starts to put out lower voltages after 5 to several years even without failuer.
 

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Quote:
Originally Posted by JOHNnDENVER /forum/post/12860850


I think one or more of your CRT's is wearing out from the descriptions.


Hard to say. The other thing that happens over time in CRT RP is the power supply starts to put out lower voltages after 5 to several years even without failuer.

What are the symptoms of lower voltages? I got the TV in 2001 so it's a little old.


One thing I noticed when I tried to focus the lenses was that it seemed I couldn't get them as "sharp" no matter how hard I tried...


Are there still ISF calibrators out there for RPTVs? I wonder if it would be worth finding one to take a look.
 

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As mentioned, ~700 lines vertical resolution isn't unusual for a CRT RPTV. I wouldn't expect ~1080 lines for interlaced CRT RPTVs, unlike fixed-pixel displays. Assume, if HDNet has been DVRed, that reading is not in freeze frame, which usually delivers only TV fields (half frames). Here, that roughly halves vertical resolution (but not horizontal resolution).


While cleaning my year-2000 Philips 64PH9905 optics recently, I covered two lenses at a time and tweaked lens focus and the focus potentiometer for each tube by itself (using HDNet's resolution-wedge patterns). The focus pot is one of six on a small board (red, green blue pots for both focus and screen voltages); screen adjustments should be carefully avoided. Didn't improve crispness here. The lens/pot ranges for crispness were very narrow and tweaking didn't help.


If you can't see scan lines up close, that means electron beams within each tube are overlapping. Here, only saw these lines within inches of my 64" screen during, say, the first two years of use. One additional adjustment might restore scan line visibility and aid crispness somewhat: beam alignment and astigmatism, covered here for Philips and perhaps for your brand elsewhere at that location, and likely in your service manual. This adjustment involves the shape of the CRT electron beam spots.


If you've tweaked focus while in zoomed mode, as you mentioned elsewhere, those adjustments should be corrected completely for normal viewing mode.


Horizontal resolution measured with HDNet's pattern, as outlined here plays a key role in overall HD image sharpness. A few members with 1080p fixed-pixel displays have reported measuring close to 1920X1080. But many using cable STBs report only about 1300 lines with either fixed-pixel displays or CRT RPTVs. That might be a maximum with most 7"-CRT displays. (Using DirecTV for HDNet, HD Lite might need to be factored in.)


Also, as my 'here' link above mentions, some cable STBs, and perhaps the city system they're used in, make a significant horizontal resolution difference, such as my older SA8000HD and its SA8300HD replacement (see measurements given). -- John


EDIT: And as this poster reports , it's also possible CRT lens-coupling fluids have become contaminated and cloudy with age, reducing overall resolution.
 

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Discussion Starter #9
Thanks John... Beam Alignment and Astigmatism is something I could try. I did the lens focus and focus potentiometer adjustments during my last lense cleaning as well. I am using DirecTV HD-DVR so HD Lite could be an issue... but my problem is that I know it used to better with all the same inputs....


Thanks again!
 

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Quote:
Originally Posted by hoopsbwc34 /forum/post/12867821


I am using DirecTV HD-DVR so HD Lite could be an issue... but my problem is that I know it used to better with all the same inputs....

Okay. Not that attuned to HD Lite details, but long threads in the HD programming section spell out its history: reformatting 1920X1080 to 1280X1080, which could account for crispness at one time becoming softer. -- John
 
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