High speed, low phase shift capacitors

[Zenith26kc20]

At the risk of sounding like an audiophile (can't help it, I am one), Has anyone tried some of the designer capacitors (Solen, MIT for example) in the video circuits of their TV's? I may get curious over the next week and see what happens! I have to pull the chassis anyway to change the crt bias control so it may be something to try.
These caps are advertised as low phase shift/low loss and more. I have used and like the Solens in audio. Let me know!

[zenithfan1]

I too have thought of this, what stops me is the cost of those caps. Let us know if you try it, I'm eager to hear the result. It would seem that it might clean up some of the "noise" in the I.F. and video for a clearer picture. I don't see it doing much for the power supply but what do I know??

[andy]

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[zenithfan1]

Good point andy, might have to try a regular new replacement first then the overpriced one.

[electroking]

If you want low phase shift, nothing beats a plain old carbon resistor...

[old_tv_nut]

I think replacing bipolar electrolytics with film caps in an AC case (like a crossover network) could makie sense. However, all internal circuits I can think of in a TV set using electrolytics have them definitely biased one way - so replacing a small electrolytic (like a cathode bypass / contrast control circuit) with a film cap is not likely to produce any noticeable effect unless the electrolytic was bad to begin with.

[JesusJones]

Do the video chain and feedback loops.

At least within the audible range 20-20 000 hertze it should be much more linear and accurate. Causing a more accurate video reproduction(Videophile'y sounding Much?)
And for some reason I feel like it would improve greyscale. But I Don't Know!

I really wanna see you try it.

For Science!

Cheers,
Rudy


Edit:
And hey, wild your at it, bump up the vert and horiz scan rates, change the electron gun in the crt to that of a much smaller screen. And bammo presto you have HDTV

[wa2ise]

You could parallel smaller caps with the big coupling cap to bypass the bigger cap's internal stray inductance. That should help the phase shifts.

[TubeType]

Please stop! You're making my brain hurt.

[Zenith26kc20]

Changed the CRT bias control (melted a long time ago), set the screens, drives etc back up and let it run for an hour.
Replaced the coupling to the video output grid. Weird!!! The brightness control had a delayed effect and the picture was slightly smeary. Checked the original, it was perfect! On value and no leakage! Pulled the Solen, checked it. It was supposed to be .1 mfd. It was a whopping .51 mfd. This threw the brightness control a new one as it biases off a 3.3 meg/330K ohm network. Took too long to charge from the cap being way too large.
Got curious. Put a high voltage (1200 volt safety cap) in it's place. I can't see a difference yet. Operation is normal again though. I'll try some in the color circuits next.

[Zenith26kc20]

With the High voltage capacitor installed the coupling position of the video output grid coupling, after comparing the Maggie to the shop CTC-156, the high frequency content is finally besting the 156. I like it! I had to put a couple of test extensions on the chassis underneath to compare the original and the new (real pain to hang upside down to install parts). More to come next week!

[JesusJones]

Sweeeet

Keep it up. And don't forget before and after SHOTS!!

Cheers,
Rudy