CTC-15 restoration

[DaveWM]

you said all the vertical caps, if that does not include the boost filter cap, check that as well. Its a .1 or .22 can't recall, mounted on the sweep board. This is if the other stuff does not help. there is also a resistor in the grid circuit of the vert multivibrator that is pretty critical, 24k I think, look for the gold band 5%.

[6GH8cowboy]

I'll look for those two parts in particular. The cathode cap is on the change list for sure. I'll also be checking for about a 150 ohm path between convergence pins 1 and 2. I'm going to verify the B Boost voltage but I suspect it's close as the screen for each gun is pretty perky.

Parts changed

Pictures added

Still suffering a lack of vertical deflection.

I now have a remote unit but I believe its for another RCA set but I think it could work. A freq counter loosely coupled shows 35 to 50 khz depending which button is pressed. That seems a bit broad to me and there is only one adjustment. I was expecting there to be only 1.5 kc apart for each function.

[6GH8cowboy]

This set has a CPT10-A reciever and the handheld does not match the Sams schematic. The diagram shows a different component layout and has trimmer-caps to tweak each function.

The handheld I have has only one adjustment and the measured freqs dont match up even close to several functions. Some do. The only ID on the inside on the PCB indicates E-143365-1 RCA-5.

The only trimmer was soldered so it was replaced. The channel freq is right on and I'm back to the original issue. I get the idea this is not the remote for this chassis or I'm going to have to play capacitor roulette for each function.

Is this the wrong one? Is there a practical solution.

[Charlie]

Did you change the lytic on the sweep board? I think it's 50uf... can't tell in your photo if that's a new sprague or and old one in the cardboard sleeve. That capacitor usually opens up the picture if adjustments do not.

Other than your picture not opening all the way, it looks really nice. I'm jealous that your Vislanda is a remote set. Mine is not.

[6GH8cowboy]

That (cathode) cap has been replaced and checked and subd.
At this point all parts have been replaced with the exception of the yoke and V. transformer. The path through the convergence is good at about 130 ohms. I have not replaced the VDR. B- boost checks about 1100 volts with a triplet meter.

Wish I could say this ones mine. It belongs to a local VK collector, I'm helping him out with the varied technical issues.

This one (CTC-15) is a beast as far as this vertical issue goes. This is a high hours set and had a number of problems you'd expect to sometimes find, but all at the same time. It also has had a lot of previous attempted repairs.

Odd thing is I recently had a CTC-16 that fought for Vertical as well. It just barely makes it and I'm taking a wait and see, figuring if it gets worse, it'll be easier to find.

[miniman82]

Hard to tell if it's a linearity problem or height problem, can you post a pic with crosshatch pattern? If it's not lin, is the correct voltage reaching the vert out tube plate? If not, I'd replace the vert out trans or sub a yoke to see if either of those solves the problem.

[6GH8cowboy]

This is the best I can get at the moment. The top tends to crush. I can get linearity with a smaller sweep but if I go for max the bottom streches and the top flatens out. I don.t think the DY is bad as there is not a whacked geometry. The VOTrans is quiet and cool. With the service switch on there is about 396 volts on the plate of the output tube section, Grid 0v and cathode 85v. so its pulling current and the plate volts seem healthy. I suppose there could be a shorted turn but I would expect a more visual symptom.

Now since the last chassis removal the brightness control has stopped working. Wish I had a jig and more room. argh...

[mstaton]

Does the vertical centering pot work? I has 2 go bad in my 2 16's and cause strange problems. Might just be a broken wire on the brightness pot. my 9 has extreme hours on it and all the wires want to just fall off when you look at them wrong. Looks great otherwise.

[Charlie]

I can see a white ceramic tubular capacitor under the deflection board. Don't know what it's for, but I bet it needs to be replaced. Those are never good.

[tvcollector]

mstaton, In case you didn't know, this is the same set that was posted under Curbside months back ago, which you posted.. I found a shipper on U-ship to Florida..

http://www.videokarma.org/showthread.php?t=254480

I'm surprised it's still listed on Ebay.. I guess it hasn't been the three month mark yet..


The vertical is starting to look better and better.. Hopefully the Remote issues can be worked out..

I found other threads on here who have had the same issues with this and the 16 chassis.. seems to be common

http://www.videokarma.org/showthread...ighlight=ctc16

http://www.videokarma.org/showthread.php?t=147493

[6GH8cowboy]

That white cap is the buffer on the plate. A .001 2kv cap. I replaced with a 1600v unit and later put this NOS piece in to see if it made a difference. The centering control has been replaced by a previous person, measures 12 ohms and adjusts smoth on the screen. It looks to be good and both secondaries of the VOT to the centering pot and yoke as well.

[DaveWM]

there is a gold banded resistorcircuit of the vert multvibrator, 24k R508 and check the 2.7 meg R515. The 24k can make a big diff in vert sweep

[miniman82]

After seeing the new pics, the linearity looks pretty decent- it just lacks height. I like the idea of replacing the cap across the vert out primary, that could cause issues. Also make sure the lin and height pots haven't drifted, if you haven't already. You're almost there!

[mstaton]

Just a thought, are those TV shows in widescreen? You may be trying to stretch it out too far. Probably not, just thought I'd throw that out there.

[6GH8cowboy]

This is being fed from a converter box, but the vertical is genuinely underscaned. There should be margin to spare. The 24k resistor is dead on. I did notice I replaced the .036 with a .033 so I added another ,0039 across it but it made no difference at all.

I have noticed on a schematic on boxcarcabin.com the Vert lin. control is connected to B Boost only. I'm using the Sams and the Lin cont is across 405v and Boost. Any thoughts.

Basic power supply volts are good and the lytics have been subd. I tried a different tube earlier from another set with no change.

This would be soooo much easier if I had a test jig.