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Originally Posted by Steve D.
...so I depend on the cable feed. This tends to overload the front end of my CT-100 on high band vhf channels and is only marginally better on low band most of the time. Any suggestions? Steve D.
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Hi Steve,
The one time I had a cable connected to my CT-100 (for a few days almost a year ago; no cable box).
http://home.att.net/~pldexnis/potpou...echannel78.jpg
Unlike on the above example that was a UHF experiment, on some regular VHF channels, I was getting 'swirly' things not seen of a modern cable-ready set running alongside. But, here are two simple things that were effective clearing up a noisy picture in my set.
Three-hundred-ohm twin lead is designed to be supported with standoffs. If you open the back and remove the top of the CT-100 cabinet, you can inspect the lead dress from the antenna connector on the rear to the KRK12C turret tuner. RCA used two plastic cable clamps to keep the lead from interacting with the rest of the chassis. If these clamps deteriorate, as do the similar plastic clamps on the delay line, the 300-ohm balanced line can flop around and generally not be where it should. I've replaced the long-gone clamps on my chassis with loops of spaghetti under the original clamp screws.
A second and more important point is that the old tube sockets should probably all be changed in the IF strip and tuner. This of course is possible but not very practical, and it would increase the need for a full IF alignment. [ah, to go go back in time and watch the test and cal guys align a CTC2] A much easier and quick maintenance procedure for a possible marginal socket is simply to rock each IF tube in place in a rolling motion to introduce abrasion between the tube pins and the tube socket. Very simple and it works. I leave the tubes standing straight up and firmly seated against each socket. Yes the tubes are hard to reach and I most of the time do it with the power off. But you can get to the first two or so IF stages without sliding out the chassis.
Although the tubes in the tuner have higher quality sockets, I re-seat the RF and IF amps there too and recently stabilized a microphonic-like ripple somewhere in the luminance path using this technique. A light tap on the floor next to the set intermittently caused the rippling effect, which is now in the 'repaired' category after simply re-seating the tubes (but it took a few times).
You mentioned using a DVD to drive your set. Someone here on AudioKarma mentioned the 1938 Technicolor Robin Hood. Bought it and it makes a great color demo as the movie was shot in the three-film-strip technique using b&w film to record the color information. No dye deterioration possible; it makes for some spectacular vintage film color.
For maximum fidelity I stay away from the composite domain with this arrangement. Use S-video to connect the DVD player to a late-model S-video VHS recorder, which is used to generate the modulated RF on channel 4. I'm hoping since it's an improved VHS format recorder that the manufacturer spent a bit more on the RF modulator too... but who knows. Anyway, the S-vid link has gotta help.
Pete