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#1
05-09-2022, 10:43 AM
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The meeting is now over and was a general success. The two talks were unusual but excellent.
The "repair" days on Thursday and Friday did not go as well as one could have hoped. I worked on the CTC-5 Deluxe which started with a nice blank raster with bad gray tracking. Fiddling with the connection to the house RF distribution resulted in a terrible picture. The fine tuning did not work. This was traced to a bad clutch, which a bit of "working with" got going "well enough". I set up my own signal setup (Blu-ray player and B-T agile modulator) which resulted signal which varied with channel. I settled on Ch. 5. But I forgot the remote so had a limited of patterns (which did include crosshatch.) (I use patterns of my own divising, .jpegs on a USB stick.) I tweeked the convergence just a bit. The AGC did not work so I had to use an attenuator. Overnight I visited Walmart and got a universal remote that allowed access of color patters, clumsily. The gray tracking was fixed in two minutes into "excellent". Thursday I attacked color. This set is unique, using R-Y and Q demods. The Q was dead. A lot of time was spent doing resistance checks using tube extenders, and swapping tubes in the color section. All the tubes were functioning somewhat but the resistances were high. I brought in the scope and determined that there was both signal and 3.58 drive to boith demods and that the matrix at least a bit functional Hours were lost because I was using the wrong AGC control! Once I found the right one the AGC started at least a little bit. The color was all in the R-Y channel --- no Q thus no green or magenta. Finally I broke down and with several actual "Experts" standing by got out the magic diddle-stick and tweeked the color demod angle looking at the screen. This resulted in all colors at least a little. We ran of of time. Picture is horrible but colorful. I think that at least two full days of alignment is needed after a careful resistance check and re-resistor session. Probably three days total on the bench. This set will not get better without a complete total alignment. The B&W bicture is rather ringy on all channels, especially 3. It was found that the RF feed was bad ... including some sort of interference. It was changed to a good one. Other sets being worked on fared worse. The CT-100 never got color. The Royal Soverign was never made watchable. There was (as far as I know) nothing wrong with the Philco Predicta and the repaired feed gave a very nice picture. The two main CBS color sets were generating their usual gorgeous pictures of Dorothy. Only one prewar US set was working, a non-RCA TRK-12, giving a mildly dim but OK picture. One prewar British set was working, a Murphy, but it was misadjusted so badly that only a "random twister" could have done it. After quite a while trying to figure which knob did what I got a watchable but dim picture. Somebody earlier had adjusted the WWII military iconoscope camera and it was producing a really excellent picture for the low light level it gets. It had a really squared up raster and a perfectly round test circle. 
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#3
05-09-2022, 07:34 PM
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Quote:
not only blue bar matching but red and green bar matching I got all three almost perfect, but at that point the color frequency response was extremely bad. The alignment must be horrible. I've never found an old tube set with anything but terrible alignment except my TRK12 which came to me untouched since worked on by RCA research in Camden, around 1946. Its alignment was identical to a perfectly aligned CT-100. My Pilot 3 incher and one Hallicrafters electrostatic set were actually oscillating! Doug
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