Quote:
Originally Posted by Chris K
Hi all. Lots going on here but that's life. All the traps and transformers have been nulled and peaked according to the new testing scenario laid out by Penthode. I'm now at the point of adjusting T-1 and T-101 with a sweep from 20-30 mc symmetrically around 25mc. It's kinda a mess. Amplitude is low and it doesn't look anything like the two peak response curve in figure 15. I'll post some pictures shortly. I hate to start thoughts of feeding composite video in this but I'm starting to consider that option. I have checked the multiburst bar sweep and the resolution isn't much better than it was when I started all of this. Maybe this TV was too much too soon for me. I did get further than I ever have in the past and I've learned so much about how these circuits work. Right now, the challenges of this are blocking work on other projects I want to get into. Other than holes in the chassis for the RCA plugs, there's nothing irreversible about cutting in with a signal at the video and audio amplifier section. I'm willing to give this process one more shot...start to finish. I mean all the way back to de-tuning T-113 in step 1. Despite Penthode's helpful suggestion with the alternate method for tuning of the video section and being pretty confident in getting the correct responses on the VTVM, there's still no change in the quality of the picture and, as I said, the T-1 T-101 tuning step is a mess on the scope despite hooking up the 330ohm resistor shunts correctly and feeding in a sweep signal at a number of different amplitudes correctly. Like I said, I'll give it one more comprehensive shot but if it fails, well, I have some decisions to make. Thanks all.
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Perhaps the best thing is indeed to make a non-invasive direct video feed (without opening holes in cabinet or chassis), playing with that, and other things. Then, some time ahead, you can return to this issue with "not loaded mind" ("not tired mind" (I forget what the term for that in English).
Sometimes for me, for example, heavy projects (for the mind) I end years after the starting, after some big pause.