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  #16  
Old 03-31-2008, 03:18 PM
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Digital Camera Screen Capture

I'm using a Canon S-40 with 4Mpixel and 3X optical zoom. My photo processing program is Ulead PhotoImpact SE which I've used for years. I intend to checkout the suggestions of " old_tv_nut " but have tried just about every combination already. Maybe there's a silver bullet in there somewhere? I even tried my wife's 7Mpixel Olympus with 18X zoom, no better.

Presently I'm attempting a precision dynamic conversion on the CTC2B which feature separate vertical and horizontal coils on the three magnetic assemblies. Uses 9 pots and 3 trimcaps which should reduce the interaction of horz and vert during optimization. So far I've come close but not good enough. Its really driving me crazy going round n round, getting nowhere.
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  #17  
Old 03-31-2008, 09:16 PM
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Quote:
Originally Posted by Tomcomm View Post
I even tried my wife's 7Mpixel Olympus with 18X zoom, no better.

Now that doesn't seem right - you should be able to get a reasonable result with one of these two cameras - hope your experimenting bears fruit.
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  #18  
Old 03-31-2008, 11:19 PM
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  #19  
Old 04-01-2008, 06:19 AM
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...And now, we're gonna flush NTSC down the terlet. Nice. Way to go, FCC..
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  #20  
Old 04-05-2008, 04:30 PM
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21CT55 Convergance and Screen Capture

I've finally got the dynamic convergence acceptable, not perfect. Best advice..... "Know When to Quit" or you'll drive yourself nuts!

The CTC2B's original 21AX22 had the first magnetic convergence and was straight foreword but highly cross-coupled. No control was completely independent.The very next RCA, the CTC4 ,was simplified and designed for quick setup. All remaining RCA's continued refining the dynamic convergence and presumably improved its performance??

Once I had better convergence I noticed a major improvement in the fine detail inthe screen pictures, as expected. I then went back to making digital camera screen-captures as close to the real thing as possible. The CTC2B using the 21FBP22A was capable of greater brightness dynamic range then the Canon S-40 4mpix! Even going fully manual shutter speed and aperture settings with ISO 400, I couldn't capture the dark areas on the screen without driving the brighter areas into saturation.

The Canon's native resolution is 2272 X 1704. My CRT computer monitor max is 1280 X 1024 but I use 1024 X 768 for all my photo editing and display. This mismatch, in addition to the TV's CRT pitch makes for hideous moiré on lmost all captures. I started to mess with my Ulead PhotoImpact editor to reduce the 2272 X 1704 Canon shots to exact multiples of the monitor's 1024 X 768 resolution. At 1:1, suggested by "old tv nut", the moiré was greatly reduced but replaced with a uniform artifact that gave a grainy affect to large areas of saturated color. I then went to 2:1 or 2048 X 1536 resolution which was much closer to the Canon's native. The residual moiré was no worse then the 1:1 and the artifact remained, but was much finer and not nearly as noticeable. Since the edited picture had twice the resolution of the monitor, the displayed fine picture detail was obviously better than the 1024 X 768. Needless to say, work will remain in progress in this picture quality area.
Attached Images
File Type: jpg Copy (2) of Copy of 175-7529_IMG.JPG (95.1 KB, 116 views)
File Type: jpg Copy of 175-7565_IMG.JPG (75.8 KB, 106 views)
File Type: jpg Copy of 175-7563_IMG.JPG (101.0 KB, 100 views)
File Type: jpg 175-7579_IMG.JPG (107.8 KB, 99 views)
File Type: jpg 176-7605_IMG.JPG (104.0 KB, 95 views)
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  #21  
Old 04-05-2008, 10:21 PM
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I see line structure in all the pix except the convergence pattern. Since I don't see any shutter effects, I presume your shutter is slower than 1/30 second and captures both interlaced fields. Then the visible line structure could come from some degree of line pairing.

Something to try: turn the vertical hold very slightly and see if the line structure changes.

Regarding the moire' problems - are you defining a picture reduced to the monitor resolution as 1:1? That's not what I meant. I meant the same size as the camera original (2272x1704). Set the photoimpact zoom at 1:1 to get this. The picture will exceed the size of your monitor screen, but don't worry about it. You should get the least moire' problems with this setting. Then, if you do see moire' with smaller zoom settings, you can ignore it since you know thje capture is good and it's just a display problem. Once that is settled, you can work on reducing the size for posting. Whatever you do, view the reduced picture at 1:1 zoom setting also for minimum moire'.

One other thing to try, in case there is some problem with the scaling between the monitor native resolution and the 1024x768 input you are using, is to temporarily set your video card to 1280x1024. You may not like the small icons and text you get, but you will elminate any possible scaling problem there. In general, it's best to not do any resolution changes anywhere along the chain when trying to determine if the original capture is clean.

Your comment about dynamic range is interesting. I see you are using the video essentials DVD to feed the TV. Your computer monitor must also be set to the correct black level, or you will have dynamic range viewing problems. Check out http://www.daproducts.com/calibrate/ for example. It is also possible to use the video essentials DVD to calibrate video playback on your computer, but caution - this calibration will occur within the
dvd player program and will not adjust still image viewing with other programs.
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  #22  
Old 08-05-2008, 05:24 PM
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21C55 #B8802897 installed

The 21CT55 with a 21FB22A rare-earth CRT is operational and installed in my tiny lab where it will stay as long as I stay. IMHO, it has demonstrated it is capable of displaying a picture that is comparable to a Sony PVM1334 broadcast monitor at normal viewing distance of 3ft to 8ft. The comparisons of Sony vs RCA is presented here:

http://www.picturetrail.com/sfx/album/view/19914223

Like all my projects, work will always be in progress. Right now I am attempting to replace all the generic ferrite cored low SRF video peaking and filtering coils I used to replace the original RCA custom air cored, high SRF, universal wound coils that open circuited. Hopefully this re-coiling will reduce the slight ringing on video transitions and the chroma bleeding into the Y luminance video due to improper demodulator filtering. Click thumbnail to enlarge, than click lower right corner to super enlarge....Tom
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File Type: jpg 186-8627_IMG.jpg (68.3 KB, 90 views)
File Type: jpg 185-8561_IMG.jpg (110.9 KB, 109 views)
File Type: jpg Copy of 185-8512_IMG.jpg (111.3 KB, 125 views)

Last edited by Tomcomm; 05-28-2009 at 12:23 PM.
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  #23  
Old 08-05-2008, 06:00 PM
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Wow...

That's all I can really say.

One of the rarest TV's in the world, akin to the CT-100, except with a larger screen.

Wow...
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  #24  
Old 08-05-2008, 06:06 PM
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  #25  
Old 08-06-2008, 12:28 AM
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  #26  
Old 08-06-2008, 12:44 AM
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Thats awesome! Just think, these are photo's we are looking at. I can only imagine how much better the picture looks in person. Great job!
-Tony
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  #27  
Old 08-06-2008, 09:39 AM
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Those screenshots are absolutely STUNNING!
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  #28  
Old 01-05-2009, 02:21 PM
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Questions on the 21CT55

After a few months activity on a couple of my 70s rectangle ss tvs I got back to my "custom installed" 21CT55. It had been ignored for about four months and I was curious if would come up with the same demonstrated picture quality it had before. It did after a 15min warm up and all was well.

I'm now running the AC power input off a computer power stabilizer and a big Powerstat so I can maintain the same voltage out of the silicon rectifiers that replaced the original selenium rectifiers. I adjust the Powerstat for a nominal B++ of 400v specified by RCA. This occurs with an AC input of 110vrms. Since I don't have access to an ultor HV meter probe I run the HV adjust fully cw max. At this setting I read a boost of 1010v! Nothing seems stressed, everything in the HV cage looks normal and the HOA 6BC6 has no plate glow or blue gas. I get very good focus and run the horz size at minimum. Gray-scale is near perfect, with very good PQ. RCA rates the
21FBP22 ultor at 27.5kv max. I may be exceeding this, but ignorance is bliss.

The only real problem I see with this operation is a very slight uniform screen glow in a totally black room with no video applied and the brightness, contrast and color fully ccw. No glow is seen at turn on and holds black for about 5min then ever so slowly starts becoming noticeable. This increases with time and becomes quite noticiable when compared with the Sony monitor after about 30min. I reduced the HV adj to min with no difference in glow.

I used my newly acquired Sencore CR70 (ebay $149) to check for element leakage that prevents complete gun cutoff, all read good. Cutoff on the CR70 all made the Good Box and all emissions were at half good meter reading. the lifetime test on each gun went into the bad zone when the heaters were reduced 25%. Seems like a good candidate for a mild Auto Restore. Only problem is the CT70 increases the heaters from 6.3vrms to 12.5vrms for 40 seconds during each gun test! That bright yellow heater glow scares me on such an old crt, so I'm reluctant to rejuvenate.

I would appreciate any comment on this cutoff glow phenomena and the advisability of submitting this really neat crt to unnecessary abusive. Tom
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  #29  
Old 01-05-2009, 03:25 PM
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Your set works and looks gorgeous! I would just use the 'ol 8 volts method if you are unsure of a restore. It sounds like that is all you need. I would let it sit at 8 for about 2 hours and then test after it has cooled down. I too have the CR-70, I don't often use the restore, but did try to damage a dead CRT one day just to see what I shouldn't do, well, it just wouldn't hurt it. It shut down before any damage was done. This almost dead CRT is still functional. The CR-70 is probably one of the safest on your tube. But, like you said, why take a chance on such an old and rare CRT. The most I have used the auto-restore is on a weak tube that didn't come back on 8 volts. I interrupted the restore after the first 7 or so second burst that it gives. I didn't let it go all three times as per the instructions. It also says that interrupting the restore is ok if you want. Tube came back nicely. I try to be as gentle as possible.
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  #30  
Old 01-05-2009, 05:54 PM
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