Example, there looks to be a bumblebee capacitor on the horizontal PCB, cant see what the others are. :O

It's all been recapped... At least 45 capacitors. Wowiee. Maybe my Dumont ra-103 had more but I'm not sure!

I love finding former wierd repairs... I was investigating why I need more focus range so obviously I check resistors after the 1v2. The bleeder resistors were all high, they should all be 10meg. One was 16 meg, one 14 and the other actually close at 11 meg. Not an issue there as I did buy some 10meg two watts. Being NOS resistors most tested high so I found the ones closest to 11megs each. None were bang on 10, not even close. I'll get those in after I finish this post..

The former technician repair job that surprised me was the bit of wire jumping over the two 1 meg load resistors R155 and R156. I removed the jumper and tested the resistors and they are spot on 1 meg. The other bodge I found was a ceramic cap from the 1v2 cathode to ground. A bit of filtering perhaps? It looked crunchy and they ripped part of the cap where the wire leading into the cap goes. I tossed it. No value printed I could find.

Is this another CTC-7 mod they were applying or was this them being lazy because they didn't have 10 meg bleeder resistors in stock?

I'll have to wait a couple days to get the chassis back in to evaluate these issues with the focus and to see if my R172 replacement gets my color to return. I'm waiting on some .01 ceramic caps to replace the ones going to V22 as they looked bubbly and hot. I want to reduce my chances of burning out my replacement 6.8k R172 replacement.

--
Matt Davala

You will notice in the Deluxe chassis a high wattage power resistor dropper I recall either in the oscillator or chroma bandpass amp section. The power dissipation created a lot of heat which damaged the resistor it self and a coil. I repaired it by mounting a lower value resistor in its place to reduce the dissipation and mounted another power resistor elsewhere on the chassis in series to allow it to dissipate the bulk of the power without burning up anything around it.
You will see the resistor I am talking about. Check it is not open and if there are any charred components around it.

I'm pretty sure that's the one that went open on my set. I'll check the coil for continuity. The chassis above the resistor is definitely darkened. It's interesting the sams and rca service info differ on the value of the resistor and what B+ voltage is tapped. Sams has a 390V B+ to a 10k 7 watt resistor yet the RCA service has 300V B+ and 6.8k 7 watt. Mine had the 6.8k and I installed it closer to the chassis to help dissipate its heat better.

--
Matt Davala

So frustrating, I replaced R-172 and R-173 as they had both gone open and I still have no color. I have a good black and white image but zero color.

When I adjust the color killer I get a momentary change of hue, but still stays monochrome. Hue control does nothing. The AGC threshhold control in the rear does nothing either.

I had changed out C144, c145 and C151. I guess pull the chassis and investigate the color killer..... Hmmmmmm......

Geeze how did I miss M8? The color killer AGC diode.... Its just a switching diode and I've still got a pack of them in a drawer.

I'll replace that and check some of those resistors in that circuit.

--
Matt Davala

Nope that didn't do it. I did find an open 10 meg resistor connected to the color killer control. I replaced another 10 meg and two 1 meg resitors that were slightly off value. The diode was replaced although it tested fine.

Time to pull the chassis again. What a pain.

--
Matt Davala

Tube resistance checks tomorrow! Lets hope I can find an issue I can work with.

This is the point where an oscilloscope would be extremely advantageous to finding such a problem.

Looking for the correct signal starting at the color takeoff coil (L36) and seeing if W23 is correct or not, (taken with color rainbow input), then onward to W24 at the color control, (bandpass 1 out), and next W25, (bandpass 2 out).

This should give some idea as where you are losing color.

The CTC-5 has all the yoke plugs at the back of the chassis so if you can find sturdy box or cooler approximately the height of the rear chassis shelf you can test the chassis outside the cabinet by setting it on a box behind the cabinet with the back of the chassis facing the cabinet.... You'll also want a clip lead between the metal parts on the CRT and the chassis....with sufficient cunning you may be able to set the chassis on its side and have access to everything while its connected and running.

L39 primary was open. I removed the transformer ungracefully(I'll have to hot glue it back in place.. oops) and saw the issue. It is carrying plate voltage for the second bandpass amp. With such fine hair RCA used as wire it vaporized at some point in time. I should have asked my wife for a magnifying glass but I searched and saw the tiniest smidge of wire coming out of the transformer. I really had no hope of saving this transformer so I just went all out with solder and a 1 piece of copper wire. Melted the heck out of where I suspected the lead to be and after a half dozen tries I now get continuity through the primary. 8ohms just like the good book said it should be. Will it hold up? Doubtful but I tried.

Guess I'll get it back in and see what happens...

Where can I get a backup transformer? Only an RCA part number 102259, no one else made a replacement.

--
Matt Davala

Finally I got it. Seems my transformer "fix" is holding. Definitely seems like its drawing just a bit more power than it should at 117volts. 400-410 watts. Almost 3.85 3.9 amps...

I'm finally bringing this into the house to finish the convergance adjustments. I'd been on the ground in the garage and its very uncomfortable. My wife wants to put in in our living room replacing our 1955 B/W set we'd been using for well over a year.

I'm sure I'll be back on here soon whenever the next part fails! The set is going to cook with the back cover on.

Thanks everyone for putting up with my posts!
-
Matt Davala

:thmbsp:

The CTC-5 made it through the Hobbit DVD reliably. I wasn't sure how my bandpass transformer fix was going to hold up. Its so nice to have color and it looks so good on the 21AXP22A

The sound out of these speakers is amazing!

I'll try and not play it too much at one time to avoid stressing the flyback. Our B/W set we had in the living room would run 10 hours some days straight. I'll not be doing that with the CTC-5.

--
Matt Davala

Not so fast....Watching the set last night I would loose horizontal lock and was having to tweak the horizontal pretty far to get lock, nearly full clockwise. Then it would pop out of sync and I'd have to go to where it was originally set. I did this at least 4 times. Then after 4 hours I couldn't the horizontal to lock at all and the width shrunk too.

I tested the 6cg7 tube and found it had a short and wouldn't test on either section. I popped a brand new one in there that tested great. Same issue, no lock and poor width, assuming low high voltage. I pulled that 6CG7 out and it showed a short now! Thats not a cheap tube to be wasting away troubleshooting. So now I'm out of 6CG7's until my ebay order of 4 of them ships monday.

I'll do some testing in that section, there really isn't too much going on in that board. Any ideas on what would cause the tube to short out internally?

I thought this set was ready for the living room! I should have done the burn in testing in the garage.

--
Matt Davala

Even though the SAMS shows no cross for the RCA 102259 x-fomer, one may have been made after it was printed, and COULD be listed in a later Stancor or Merit,Triad,Thordarson, cross reference manual.

I'm sure someone out there has them and can see if any type of sub exists!

As for the horizontal issues, if you have not already done so, make sure there are no out of tolerance resistors in the circuit, having no VDRs in this set in the sweep area makes it prone to out of tol parts and aging more than the later sets.

Also, since parts were replaced, it's critical to go through the steps shown in the SAMS under Horizontal Sweep Circuit adjustments, this will get things most stable and lower the risk of frying the flyback.

OK, something is not making sense here, you put in a NOS 6CG7 and it blew right away?
You say it shorted? How, H-K?
If this is indeed the case, then you have had something critical fail in the area to cause it to push the tube way beyond it's max ratings if it shorted that fast, like an open resistor or shorted capacitor.
You should be extra vigilant in looking at every related part and finding the cause before destroying another way WAY overpriced tube, thank you audiophiles very much! :(

Thats right it caused the new tube to short out immediately. I recapped everything leaving a couple of micas. There are a few resistors there too. C-115 if that shorted it would pull the grid voltage way up. I'll swap that one and check those resistors as there are a few there.

Unfortunately, I'm away from home for a couple of days at work and then I've got to study for my yearly recurrent training early next month. I'll only be able to dedicate a short amount of time at this for a couple weeks.

A 20$ 6CG7 gone in a flash...
--
Matt Davala

Yeah, it's those 1k mica caps that I'm a bit suspicious of, if one or both is leaky/ shorted, it may drive the heater/cathode v way to high, you might see this on resistance checks, not sure.

But new caps are not TOO much.
82 598-CDV19EF820JO3F
330 598-CDV16FF331JO3F

Mouser parts.

however, do they really have to be mica?

81-RDE5C3A331J2M1H3A
75-561R10TCCQ82

my set has all ceramic capacitors.

Perhaps someone with a ctc-5 can give some insight,

Ordered! Thanks!

Looks like C115 is in a rectangular package, I assumed its mica VS round ceramic.

that blue one is a modern Multilayer ceramic capacitor, like made for SMT, with leads on it for through hole.

Wax Capacitors in CTC-5 Set
 

There were some RCA black and white sets 20 inch and above, in the 1950s, that had over 50 wax caps. RCA loved them waxies. Part of that is the belief that tubular capacitors automatically have more consistent high frequency response. Admittedly it is much harder to properly select ceramics for high frequencies.

I should give an update! After completing my yearly recurrent training I was able to dedicate time to troubleshooting the horizontal section. Symptoms were horizontal off frequency, low HV.... and it caused TWO 6CG7's to short out internally.

I took three micamold style caps out of circuit and tested them. C115 was the culprit, leaking at only 50 volts. It's supposed to be a 1000-volt cap. I also replaced a couple out of tolerance resistors, nothing too crazy. Two 82K caps were both showing 91k.

I'm back to having a running CTC-5 although I'm dreading a full convergence alignment. The sides are really bad.

--
Matt Davala

The convergence of my CTC5 wasn't bad once I read and followed the CTC5 service manual. The convergence process is somewhat different from later sets.

I have been able to achieve good overall convergence but it takes patience.

Also be aware of the general complaint of low high voltage. To get a bit higher voltage and improve regulation, I replaced the HV rectifier with a solid state 3A3.

I'd describe it as follows:

The CTC-5 does not have diodes to clamp the dynamic waveforms at the center like later sets, so in the CTC-5, points halfway between the center and edge stay motionless while the center moves the opposite of the edges. The trick is to rough in the DC in the center, then adjust the dynamics to get parallel R, G, and B lines, then fine tune the DC for best overall (and then maybe retweak the dynamic a tiny bit).

Hope your DC control pots are in good condition and not burned just at the proper setting point like mine were (both originals and replacements from a parts donor).

100 ohm carbon pot with tap at 25 ohms IIRC. Really pushing the limit on low total resistance for a carbon pot. I made up a substitution with 6 wirewound pots and three switches to pick a tap just above or just below or at the nominal tap point. If I was doing it again, I'd be tempted to try subbing a later cloverleaf with permanent magnet DC adjustments, but I don't know if the coils would be right for the dynamics.

1st band-pass transformer failure
 

Been a bit since I posted. The set worked great for one good 10-hour watch session. Then on the next power up I had no color. I assume the surgery I had to do on the 2nd band-pass transformer didn't hold up. You can see a few posts back the repair I did. I'll try another poke with my soldering iron at it....

As for replacements there are some bandpass transformers that look similar on ebay. How critical is it that this needs that exact RCA 102259? Seems like that is unobtanium. I asked Moyers already.

Does anyone have a scrapped chassis for the CTC-5 deluxe that they could pull a replacement from?

Thanks!
Matt Davala

ISTR David Goodling mentioning having a CTC-5 parts chassis. Might be worth talking to him.

Another thing to consider is the CTC-5 had a deluxe and a super chassis and one of them had an extra tube in the color circuit and thus a different color circuit....So that coil may or may not be different between the two different CTC-5 chassis sold.

I sent David Goodling a private message and got no response. Does anyone have his email address?

It seems I'm at a dead end with a burned bandpass amp transformer.

Thanks,
Matt Davala