there is a really fat white strand on the blue screen pot, where the 970v hooks to it to the can of the pot that should NOT be there,,, hard to get a good pic with a cell cam :/

BTW, My very first exp with a roundie was when I was very young, I'm now sure it was a RCA, CTC-10A ( The Sullivan ), I remember the metal, gloss black lacquered cabinet. It was given to my parents by my grandparents, I loved that TV...
It later developed sync problems and my dad never really put the effort into fixing it and threw it away, I never forgave him for it, they bought a tiny RCA 19 inch hybrid to replace it.
So when I saw the chance to get this CTC-16xl years later... I took it!

You DID notice the brown cap with the crack in it hooked to the boost diode as well right?

Yeah, that maroon drop C140? does indeed look damaged. Don't discount those maroon drops as being reliable...While some are still doing okay several have reported finding them drifting in value or even leaking (I've certainly found at least one leaking current)...

Here is a possible cause of that resistor failing: C140 started leaking current badly overloading the boost rect diode causing it to short, the rect then passed ~1KV AC pulses to the boost line. The boost is resistively connected to the 400V B+ rail and on negative 1KV swings of the horizontal feeding the shorted boost diode it started passing too much current through that 100K resistor frying it. Should be easy to check by ohming out the rect in both directions and testing that cap.

Yeah, that diode and cap are toast..
its a bit hard to find replacements using part numbers from a 50+ year old list, ( the resistor is easy )
i have picked mouser # 80-PHE450SB4220JR06 for the cap, and 625-RGP25M-E3 for the diode, i should prob replace that big cap and the little .001s on the screen pots, but they are most likely OK

These Panasonic caps are cheaper and a bit better for TV application (I use them in my resto work). https://www.mouser.com/ProductDetail...PvQRZAQNzTU%3D

This diode has a faster recovery time and is better suited for rectifying horizontal rate AC, and also has higher reverse voltage rating (Which can save your bacon if the ~4KV DC focus ever arcs over to the adjacent screens that are driven from boost). https://www.mouser.com/ProductDetail...OsoE%252B4c%3D

This is what I would buy if I were looking to replace those parts in my set.

total, $13 :/ its costing me more in shipping than parts :(

gonna replace the .001s out of safety, also getting a 0.47uF in order to do the HOT cathode current test, ( did not have one )

While I wait for the parts ( coming tomorrow ) , there is something I've been wondering, on the schematic, (sams ) it refers to “spark gap” in a few places, like C155, but it is a normal cap, and not a spark gap capacitor, with slits in the top like I have seen before, but, they do have the leads of this cap routed in heavy stock cardboard, in what could be a spark gap configuration, is this what they mean perhaps?

Yup!

If you ever do a late 60's-mid 70's Zenith they use two pieces of magnet wire bound together with cloth shrink wrap. Anything (or rather any two things) conductive CAN be a spark gap if you want it to be, and there were plenty of things engineers tried to make them out of.

Boost voltage restored, I now know more than I did before.

I can almost get a pic locked in through the tuner, ( sound is OK ) pic is Horrid, and rolling horz. And there is NO COLOR via the tuner,( this may be partly due to the fact that i have 75 ohm hooked to 300, but unlikely ) this reflects the original problem with the set.
BUT if I tap in video at 1st video amp, I am able to get better sync lock and even some color lock ( a lot of barber polling)

This tells me the Original problem was most likely a messed up IF section.
I have not yet checked all the resistors in the IF yet,,, I stopped after I got a signal. I guess I have to check every one now.,,
but I'm not sure what I'll do w/o a known good Sweep Marker Generator...

Get the resistors in tolerance first...If you're lucky the alignment is fine and the only drift was resistor related.

A bit of confusion on the horz sweep ( cathode current ) adjustment.
The sams shows all these steps to do it... https://imgur.com/iZJm7bP
however, here this guy, ( who puts up very useful videos ) , did not show those steps, or omitted them.
Where they not needed and just skipped? Or done but not shown? I'm not sure what I'm seeing here, and if I should use that as guide for mine. ( also being RCA, same output tube )
https://www.youtube.com/watch?v=uBkSfc0aq8U

The video is showing the efficiency adjustment as an isolated procedure and assumes the other adjustments in the SAMS are nominal.

SAMS adjustments:
The first two, for "floating" H sync, are to set the H oscillator to free run at nominal frequency so the horizontal AFC and horizontal hold controls are centered and don't have to pull it one way or the other to an extreme degree. I'm not sure, but maybe being way off center could affect the horizontal drive waveform, which in turn would affect the output efficiency.

[video procedure goes here]

The measurement across R136 is actually across R146 in the SAMS schematic on ETF. This is the HV regulator cathode resistor. Caution, it is floating at about 400v. This adjustment is to check if the HV regulator range is more or less centered. If not, you are instructed to detune the efficiency coil to get more HV supply, but simultaneously not go beyond the horizontal output cathode current limit. Ideally you should be using two meters at once (if not, you need to go back and recheck the HO cathode current).

Finally, you are similarly instructed to detune the efficiency coil slightly if you see horizontal fold-over in the picture (and should recheck the HO cathode current just to be safe).

Actually, “r136” is correct for the CTC-16X series, close but not the same as CTC-16 ( sams 0818-2 vs 0736-4)
Close, but different enough to be confusing, :/
example 3rd IF on CTC-16 = 6EJ7 CTC-16X = 6JC6A, many other subtle diff.

The only reason that I brought it up is, that while I'm playing with it ( testing / turning it on) and such, I don't want to risk any stress on the flyback, since they are so hard to find a replacement for.
As it stands now, the FB looks to be in very good shape for it's age, with no wax drip ( well, just a tiny bit) below.

Interesting...
was just poking around parts lists, it seems that the CTC16 and 16x DO NOT have the same FBT :O

16= 113992 (906160-501) and 16x = 115843 (906160-502 ) or so says sams.

Not sure what the difference is :o


Edit--

I see it now.
VERY different,
16 has HV REC / FOCUS REC of 3a3 / 1v2 and 16x has 3ca3 / 2av2.
HV/Focus circuits are quite different.

Not that I have come across a bad one yet ( that I know of ) going over the SAMS, which I have been doing a lot of, in several key places there are VDRs, (voltage dependent resistors) and I can only find RCA part #s for them listed, and little if any reference to what values they may be ( cold/hot or voltage/amp range ) , so in anticipation that IF, any of these have to be changed at any point in the future, how does one find a correct modern value replacement?

I was wondering about this as well when I was checking out values earlier today. I thought about searching the rca part number and see if I could find anything.

As to WHY, they are there, ( just a guess) is that they keep things stable as the set warms up and voltages drift, so the owner does not have to keep getting up to adjust like the horz/vert hold.
But I don't think that what is in there, behaves like the more modern MOVs...

and thus may be hard to replace.

Yeah that totally make since and they probably don't. I got the RCA copy of the schematic today. have not taken a close look at it yet, but I wonder if any info will be listed on it. though if there is I doubt its going to list what were looking for

I don't believe it.
I have started to try and check resistors in my set. (it sucks that most cant be tested in-circuit)
started checking and ran into trouble right at the start.
AGC line r36, 2.2 meg could not measure it with this cheap RS meter I have.. Off-scale high/ almost reads 20m on the 20m setting (no other higher) it cant be THAT far off :o

So it's
A: the cheap meter is lying to me and cant be trusted, or B: it really IS over 10x too high..
taking this resistor to work to check with a $400 fluke I have there.
Also getting another cheap autorange meter that goes up to 200m.

https://imgur.com/KHo8VmG

mine :o

Resistors tend to drift high (sometimes even open) and ones that start high tend to be worse so I tend to believe the meter...

Be GALD your set did not spend it's life outside getting rained on/in...I found a 1972 Sylvania in a ditch once with the amount of rust in its metal table model cabinet, rot in the back and lawn debris inside it I was sure the only good part would be the CRT...But then I washed the crap out and decided to 'play' with it. Somehow with little effort, it made a raster...Getting anything else out of it meant replacing 95% of the resistors in each stage (most were wildly out of tolerance). Somehow it made a damn good pic and decent sound for a while after re-resistoring it.

I just ordered an assortment of ½ watt metal film resistors (not carbon film, too high rfi ) Which should have most of what I find bad, I hope.
The resistor I tried to check last night checks at 31m , out of range of the cheap meter I had. :(
the new cheap meter coming goes up to 200m.
Someplace, somewhere, in my home is hiding a Fluke 73 III... :(
And I suspect that when I LEAST need it, is when it will crawl out of it's hiding place in the 6th dimension, where it has been the last 6 or more months and reappear.

Nice looking chassis! looks to be in decent shape and not much rust or anything : D

I have also ran into this myself a few time. I have had some resistors in a few of my old zenith radio sets that were meg omhs instead of low k's

also a while back I got this Klein meter, it isn't as nice as a 400 buck fluke, but its close. I love it a lot more than my old 20 dollar digital I had and it can test up to 1000vdc/vac and I have found that handy working on some of my old radios.

check it out, its just under 100 bucks

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

https://imgur.com/sob7yID
this is where my CTC spent the last 13 years or so,
and before that it was rented storage spaces, so it was always kept covered. :)

Nice! glad it was kept out of the weather

im looking forward to seeing pictures of your set when you have it running

SAMS makes it really hard to find R34,35,36 mounted on tuner :/
All they give is an overhead shot of the chassis / tuner ( page 17) with arrows pointing to a dark fuzzy low res area of where they are, no zoom of the area with the resistors marked :/

Have started on the sweep PCB. around the AGC/ sinc sep circuit.( takes a LONG time :O )
https://imgur.com/vKACCKZ

seems that 15% of the resistors are out of tol so far.

Keep this in mind when checking resistors. There is nothing that will make a resistor read high, other than a bad resistor. Any other parts of the circuit, ie: parallel paths, will cause a lower reading. I always check in circuit and if it is low then I remove it to check it. If it reads high, I just replace it. Since most resistors drift up in value, there is usually no need to take a resistor out of circuit for an initial test.

There are occasions where a resistor will drift down if it's the older phenolic-encased type. If the resistor's been running hot for a long time, the phenolic case will gradually char from the inside and create a conductive path around the resistance element. Most often seen in one and two watt units.

i just wonder how critical i should be, i am seeing some WELL within the 20% range, and others just over /under and some WAY over. I tend to want to replace the ones not "well within range...

If you are looking at carbon composition resistors, you should know that the 5% ones and 10% ones often were picked out at the end of the production line, leaving the 20% ones always worse than +10% or -10% (a "bimodal" distribution).

Also if the 4th tolerance band exists; base the acceptable tolerance on that. Usually on 60's color sets the majority of resistors will be 10% silver bands with some 5% gold for critical apps and some 20% no-4th-band resistors thrown in non-critical areas for cost savings.

If a gold band checks within 10-20% but not in it's designed 5% and you leave it, then you just missed a failed component...

example, if i check a 560k res (10% tol ) and it checks at 617k, just outside of the 10% do I let it slide? or replace to be on the safe side?

using this site to tell me the max high / low for the tol for 10% and 20%

https://www.allaboutcircuits.com/too...de-calculator/

so far, if has been close to the high or low side of failing i am replacing.

Your meter could easily be off much more than the difference between 616 and 617, so you should accept it as OK.

Ive been wondering the same thing as well. and so far if I come across one that is close or at the max, I figured it has drifted up this much may as well get it now than when it does drift out more causing a problem.

man I like that link btw! I've been doing color codes and tolerance by hand gah! lol

I'm thinking the same, After all, I got this box of brand new 2% resistors, and I DO measure them before I put them in.

I have 2 new digital meters, ( cheap ) I only got the 2nd one because the 1st did not have autorange and only went up as high as 20m, new one goes up to 200m.
Checking a removed resistor measures almost the same on both meters, ( less than 1-2% difference )
Also, when I take the removed resistors (after I replace them ) to work an tested with the high $$$ fluke, which is required to get calibrated every year, I get virtually the same results.
So, given that the set is over 50 years old, and that most resistors are of 10% or 20% how critical of an eye should on on for checking them to be on target?

If they are barely inside tolerance I leave them if the circuit works and change them if it doesn't... especially if it is something tuned that I rather try retuning by resistor than alignment...