RCA 21CT55 B8802897 is Alive!

[Tomcomm]

Well its been almost a month since I first reported to this forum the "cut-off glow" displayed on my original 21FBP22A and I described a simple test to determine if other members had similar conditions. So far I have received 4 replies, hardly an overwhelming response: 2 recent rebuilds, no glow, 2 originals, no glow. Mine is an anomaly, possibly caused by a shop poltergeist?

I have assembled a new presentation of relative picture quality between my '54 21CT55 and a '92 Sony KV27TS27 with comb filter. All pics are 1024 X 768 and should fill the width of most computer monitors. Any differences in PQ is readily apparent on these larger displays. I use Outlook Express to produce an .....ENL file that permits comparisons by slewing between adjacent inserted pictures.

Anyone interested in viewing these latest Picture Quality comparisons can send me an email to this address: [email protected]

I will reply to you, using the BCC window, with a file attachment that will play in your Outlook.......Tom

[Tomcomm]

Recently I questioned the reasons why my 1954 RCA 21CT55 with its first full NTSC spected CTC2B chassis and the last roundy 21FBP22A crt produced picture quality almost comparable with my solid-state, comb-filter 1984 and 1992 Sonys. I checked all the RCA schematics from the CTC4 up to the CTC38, tube types and also the all solid-state CTC40 of 1970. All of them have narrow bw chroma processing and hi level crt luminance/chroma combining. Did RCA ever go back to wb IQ video processing? The dramatic difference in picture quality between wb IQ and nb R-Y/B-Y was obvious to me in 1964 as related in my first AK message of March 28, 2008:

……..When I bought my 21CT55 for $50 in '64, I brought it into the house after I got it working and ran it along side my Dad's old CTC4 he left me. Both had 21FBP22s so it was a good comparison of narrow bw color R-Y B-Y vs. full bw color I Q. The extension of full color into fine detail on the CTC2B was startling! Color persisted in fireworks until extinction which I never saw before. The CTC4 fireworks turned into white long before extinction. The CTC2B carried full color way into the shadows, the CTC4 went gray to black……I get really awesome displays on the 21FBP22A with vibrant, accurate color shading. Having the CTC2B's super wide dynamic range due to full bandwidth I Q demodulators feeding low level I-Q-Y matrixing to the CRT grids only. I kept the CTC4 in the house for the kids but brought the CTC2B back to the garage workshop for further study…….

I have assembled a Flickr photo post: http://www.flickr.com/photos/tomcomm/

After selecting a thumbnail, click on “all sizes” above picture to enlarge to full screen. Two clicks of the Browser’s “Back “ returns to thumbnails.