RCA CTC-16XL Suggestions/Tips

[Rocket]

R104 has already been replaced from the looks of it. it tested out at 151k
R102 tested at 3.1 meg
R103 tested at 2.8 meg

They are all seem pretty close to spec.

Also noticed C-4 electrolytic has been replaced. Sams shows it as a 50 @ 50v and was replaced with a 47 @ 50v. that is pretty close. not sure if that should get switched out or not. I thought I read something once about its ok to go slightly above but not below spec. but that may have been for the voltage rating now that I think about it more. lol

[old_tv_nut]

Originally Posted by Rocket

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Also noticed C-4 electrolytic has been replaced. Sams shows it as a 50 @ 50v and was replaced with a 47 @ 50v. that is pretty close. not sure if that should get switched out or not. I thought I read something once about its ok to go slightly above but not below spec. but that may have been for the voltage rating now that I think about it more. lol

A 47uf electrolytic is just a standard value that replaces 50uf. The tolerance on electrolytics is usually very wide, so when 50 was specified, the actual value of an individual unit might be anywhere from -20% to +50% or so.

[old_coot88]

The vert. oscillator plate load resistor frequently goes 'waay out of spec from being hammered by high level spike. This applies across all makes and models, both BW and color. Worth bookmarking.

[Yamamaya42]

that kinda explains why your 16-xl works so well and mine does not T_T, yours has been worked on before. mine is all factory orig parts. not counting tubes.

[old_coot88]

Under the 'Suggestions/Tips' heading there's one problem endemic to the CTC-12, '15, '16, '17 and '25. That's the two ground stakes on the far right end of the chroma board. They exist in one of two states; they're either cracked or gonna crack, and should always be re-flowed as a matter of course.

[Yamamaya42]

Originally Posted by old_coot88

Under the 'Suggestions/Tips' heading there's one problem endemic to the CTC-12, '15, '16, '17 and '25. That's the two ground stakes on the far right end of the chroma board. They exist in one of two states; they're either cracked or gonna crack, and should always be re-flowed as a matter of course.

As i mentioned in the thread for my CTC 16XL, the entire chroma board had been removed at one point ( which i replaced ) when i first got it, I have now found it to be IF related ( not fixed yet ) As I can get color when I inject video at first video amp but not through the tuner. ( which was the orig problem before It was put in storage - no color )
so, they have been resodered on mine

[Rocket]

Originally Posted by old_coot88

The vert. oscillator plate load resistor frequently goes 'waay out of spec from being hammered by high level spike. This applies across all makes and models, both BW and color. Worth bookmarking.

Bookmarked! I am going to check on that one tomorrow

I will also reflow all of them spots as well, thanks for the tips!

[Rocket]

Originally Posted by Yamamaya42

that kinda explains why your 16-xl works so well and mine does not T_T, yours has been worked on before. mine is all factory orig parts. not counting tubes.

Yeah, I think this thing was well maintained and kept clean and dry for most of its life. I was impressed when I ran across it! So far digging through this chassis it looks like 4 caps and 1 resistor has been replaced. I thought I had little done until now hehe

[Rocket]

Took a break from checking caps and resistors and started working on cleaning tube sockets with DeOxit and tube pins as well all the pot controls as they were acting kinda finicky when I noticed that little pin that usually grounds to a tube shield and realized that I'm missing the shield! Took a peak at the schematic to make sure no others were missing. So I gotta find me one of them. Its on the 6gh8a Chroma Reference Oscillator. Kinda curious if any y'all know what kinda problems that missing shield would cause?

[Electronic M]

Adding or removing the shield could slightly affect the tune of the chroma osc. Shielding is important, but missing shields shouldn't cause harm...Just more noise radiated and or recieved.

[Yamamaya42]

Originally Posted by Rocket

Took a break from checking caps and resistors and started working on cleaning tube sockets with DeOxit and tube pins as well all the pot controls as they were acting kinda finicky when I noticed that little pin that usually grounds to a tube shield and realized that I'm missing the shield! Took a peak at the schematic to make sure no others were missing. So I gotta find me one of them. Its on the 6gh8a Chroma Reference Oscillator. Kinda curious if any y'all know what kinda problems that missing shield would cause?

Its prob not SUPER critical, they prob have it there to stop any RF energy from Chroma reference Osc. & control tube (v24 -6GH8A ) from bleeding out all over the place.

[old_coot88]

Not to be picayunish but the colorburst tube is not the oscillator. The burst tube supplies the synchronizing signal for the osc.

[Yamamaya42]

Originally Posted by old_coot88

Not to be picayunish but the colorburst tube is not the oscillator. The burst tube supplies the synchronizing signal for the osc.

Edited

[zeno]

Originally Posted by old_coot88

Not to be picayunish but the colorburst tube is not the oscillator. The burst tube supplies the synchronizing signal for the osc.

And they are timed by a horz pulse to grab & amp the 8 burst
signals on the back porch.

73 Zeno
LFOD !

[Yamamaya42]

It's a miracle they ever got color working at all (and still have it compatible with B/W ) And when it did work, It was... Never The Same Color! ( my electronics taught us that one )
along with...
Bad Boys Rape Our Young Girls But Violet Goes Willingly …
There was also .. eli the ice man. ( barely remember that )