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#2
12-09-2022, 08:14 PM
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You need to read on how color TV works, again. In any case, if you have the color control turned way up and the oscillator is working you should get color
at some position of the fine tuning, maybe one with a really bad B&W image, even if the IF is badly misaligned. Last spring I worked on the CTC5 at the ETF. I got color, in fact good color, but the B&W picture looked even worse than yours. I didn't have time to do an alignment. If you don't get any color, the first thing is to bring the antenna of a regular short wave radio in CW mode up to the color oscillator and see if there is a whopping signal at 3.58 MHz. Problems with the pulses generated by the horizontal output transformer can cause no color to get through the color amplifiers. The feedback in the color area is so complicated that no color is a nightmare even with a scope. Wrong color is a lot easier. 
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#3
12-09-2022, 09:18 PM
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This is prof positive that the color circuits of your TV is working.
http://videokarma.org/attachment.php...9&d=1669302177 color with direct input. I had the very same problem a few years back with my CTC-16XL. After I spent a VERY long time getting the color circuits working again after some putz messed it all up, and I had to use direct input to do so, I still could not get stable color via the tuner cause the IF was all borked because it was messed with was very obvious as the shield for it was missing. A telltale sign of messed up IF is getting good BW but crappy or no color, why it does this is complicated, but it has to do with how they took the normal BW video standard and crammed color info into it and still had it compatible with older non color sets. And most of the time there is no fix other than alignment,because otherwise the color info will be corrupted by the time it gets to the video amp, even if you get a semi good BW video. Even on my CTC-16XL I was not able to clear up the IF as good as it should be, it's like 85-90% and shows red smear, and thus I have installed bypass signal relays in the A/V lines and can change from tuner to direct input at a flip of a switch. perhaps someday If i ever get a sweep marker generator, i may attempt to bring it up to par. but for now, it's really good with direct, and fair with tuner.
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=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
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#4
12-10-2022, 10:45 AM
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[QUOTE=Yamamaya42;3247041
A telltale sign of messed up IF is getting good BW but crappy or no color, why it does this is complicated, but it has to do with how they took the normal BW video standard and crammed color info into it and still had it compatible with older non color sets. [/QUOTE] It depends on what the actual IF response is on the malfunctioning TV. Generally (but see the service data first) the video carrier and color carrier are at or near the 50% amplitude point on the response curve; the 45.75MHz video carrier is there to compensate for how the unwanted sideband is filtered out at the transmitter, and the 42.17MHz chroma subcarrier point is placed there to minimize interference in the picture from the chroma information. The chroma bandpass circuits compensate for this falling response and have to be aligned with a special setup, basically the video carrier modulated by a frequency sweep at the chroma frequency range. If either or both of those carriers is significantly out of place, there are going to be problems with the picture. Picture problems related to alignment usually end up as ghosting that changes with the fine tuning adjustment, weak or no color, excessive hue shift with fine tuning, or interference patterns in the picture, either from the sound carrier or 920kHz beat from the chroma carrier. These adjustments have to be done with test equipment, they cannot be done visually.
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Erich Loepke
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#5
12-10-2022, 05:44 PM
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[QUOTE=trinescope;324704
Picture problems related to alignment usually end up as ghosting that changes with the fine tuning adjustment, weak or no color, excessive hue shift with fine tuning, or interference patterns in the picture, either from the sound carrier or 920kHz beat from the chroma carrier. These adjustments have to be done with test equipment, they cannot be done visually.[/QUOTE] Ditto, well said. IF alignment rarely goes way out without HELP. Once I changed an IF transformer in a GE. I eyeballed thet one. The last Emerson TV's seemed to have alignment probs but they were such POS's we never dealt with it. And had a big Admiral that an alleged TV man got to with a diddle stick. We couldnt fix it & sent it to Admiral of Boston. Even they couldnt fix it. 73 Zeno 
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#6
12-10-2022, 05:25 PM
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#8
12-10-2022, 11:50 PM
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All you need for TV alignment on a "modern" 45 MHz IF like that is a B&K 415 and an oscilloscope about $50-100 if you shop around the right places.. IIRC the person who sold that set wanted like $250 for it... Another $100 for an alignment rig doesn't sound like a bad investment. I have an alignment rig just like I mentioned...I think the scope cost me $50 and the B&K cost me $25. I have been able to do a couple of alignments with it, but I'm still learning.
If you are going to screw around setting it by eye (that'll add another 200 pages to this mess easily) you should use a Philips PM-5544 test pattern (download a picture of one off the Google search, put it on a USB and use a media player that can display pictures from a USB on a TV). The PM-5544 has color bars and a multiburst pattern which gives a visual representation of the IF frequency response on screen...With that pattern you should be able to see if you are making things worse or better...If you can get it right by eye it'll be a small miracle. Quote:
I think there were other pictures where the OP had more obvious real color in the pictures. EDIT: ugh! Another stinking page.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 Last edited by Electronic M; 12-10-2022 at 11:55 PM.
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#9
12-11-2022, 06:27 AM
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#10
12-10-2022, 05:28 AM
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Well at this point all I could do is blow a lot of time trying to adjust things here and if I’m at all lucky maybe I can pull this off. Even if I had the proper things to do an alignment I still don’t know how to perform it. Since finding this trap open and restoring it the b+ voltages are finally normal the 256v is now 276v where it should be. All the time trying to make adjustments with blinders on don’t mean I’ll get it right but I’ll try.
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#12
12-10-2022, 02:07 PM
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__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
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#13
12-10-2022, 02:49 PM
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The higher up cw the brighter the screen gets. At this point I don’t know anyone in my area that knows how to do an IF alignment on this Motorola so all can do is the impossible by trying different adjustments on this set one day I’ll give up or maybe I’ll get lucky I’m into now so I don’t have a choice . I could give up now and put it in a corner and let it get dusty or I could try. It wouldn’t be worth the cost of the equipment to do an alignment and I don’t know how many pieces of equipment it would take or be needed to get the job done.
Last edited by timmy; 12-10-2022 at 03:22 PM.
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#14
12-10-2022, 04:24 PM
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Or, you can build the video amp and convert to direct input.
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
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#15
12-10-2022, 05:02 PM
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Or, just buy the equipment needed, and do the alignment. The Sam’s is on the ETF website and has the entire process. It’s not very involved, and actually pretty simple. Steps 1-4 should get you close, if you do it carefully a few times.
Get a perfect B&W picture, before screwing around with the color stuff. You can’t get good color until you get the B&W stuff right. Randomly turning afjustments will just make everything worse. This thread has gone on for 1200 or so posts. We’re going in circles now. This is, TBH, getting stupid.
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