my CTC-90 project.

[Yamamaya42]

I can already tell that I wont have THAT much to do after the first power on today I did after it being in storage since 1992, I really did not want to do anything with this set, as I really don't care for it, but my chances of ever finding a older tube based set that could use a 25Vxxx22 CRT are very small, ( still gonna keep looking ), so I decided to pull it out of storage and keep it alive.

The story behind this CTC-90 is simple ( has a JCP sticker on it but its RCA), it was given to me with a near dead CRT, I deemed it not worth the $$$ to put a new one into it, but I DID have the Heathkit TV my dad built that never worked right, and had less than 20 hours on it, the CRT fit perfectly , I don't know the exact # of it other than it was a 25Vxxx22.

The set was then loaned to a sibling, where it had light use for about 1 year until it developed vert problems, ( which I hear is common with this set ) , it was then put in storage and kept there since.

the pix
https://imgur.com/5lwxoJU
https://imgur.com/O7D8fqq
https://imgur.com/mBAq5So
https://imgur.com/Cjuau9N
https://imgur.com/TKe9hM2
sorry for getting my finger in one of those :P

as you can see, it is working very well for being in storage for so long.
I did have the yolk off, trying to see any numbers on the CRT, (none found, hidden by shields ), and I have not put on the purity magnets yet.

I did not see the vert problems that it has before, but that does not mean they are not still there, I am sure they are. All the modules are very dirty and need to be cleaned, and I need to check every part on the vert PCB.
I also need to run it a few hours to “ wake” the CRT fully before I do final setup and alignments.

As I mentioned, I really have no love for this TV ( other than the CRT in it ) , so until the very odd chance I ever find something vintage TUBE based to put it in, I might as well get this set working as well as it can!

[Yamamaya42]

after having it on for a while, I am already seeing a little bit of jumpiness in vert height, I also now remember what I really HATED about this set...

The stupid tiny little adjustment knobs in the front, that are just too damn small to get fingers on and adjust, WTH was RCA thinking here?

I think they came up with some sort of tool to slip over them to make it easier, but BAD IDEA, RCA...

[zeno]

Clean the service switch if it has one. That will fix a lot of them.
Looks like it on center back of chassis.

[Yamamaya42]

1 very nasty looking Vert module.
https://imgur.com/DBm3eRJ
I don't like those power resistors being close to the electrolytic capacitor, they are prob OK, but will replace both anyway. and check all resistors ( clean POTs )

[Yamamaya42]

Quote zeno from other thread about CTC-90.
====
If its the chassis I am thinking of it was very short lived. No value
except that its different. It was modular with a normal HOT & an
SCR in the power supply. IIRC the last RCA with a delta CRT. Only
saw maybe 10 of them, all 19" come in.
It may also be that fold down monstrosity with ITR's, we all hated them.
On latter sets vert was common problem. Always two 220K ohms &
a transistor.
====

The module is cleaned now, and the 2 220k res seem OK (r9 r6), that does not mean that I'm not going to replace them, along with the 2 electrolytic capacitors c11/c12 680uf 50v.
I really do not see anything wrong with it.

[Yamamaya42]

One weird problem I have always had with this thing, with the CRT that I put in it, even though it was an exact fit, and works perfectly, it's not OEM, and so it just happens that a safety warning sticker is in just the wrong place on it and blocks a grounding spring between the x-ray shield and tube dag, this causes a minor arc when the set comes on/ off.
I have always deemed this a minor annoyance, and not worth pulling the shield off to fix.
I have come up with a much easier way to stop it, which is to get a few pieces of emi gasket (conductive braid over foam ) and stick them in various places between the shield and tube to make sure there is good dag grounding, cost about $10

[Yamamaya42]

Parts changed on Vert module.

i still have to clean the rest of the chassis. and bond the yolk to the CRT so i can do final alignment and setups.

but as i expected, i don't have to do much to this TV

https://imgur.com/I2bueNk
https://imgur.com/bseczmW
https://imgur.com/afCgLAu
https://imgur.com/igMhmg3
https://imgur.com/2WrIEDe

how it looks with minimal setup
I still have no camera that I can set the shutter speed on yet :/

[ESigma25]

I had a set like this, until I gave it away on Craigslist to some young women who collect RCA stuff. It was a neat set but I just had no room.

[Yamamaya42]

I really do NOT like how the yoke assembly is bounded to the CRT bell area at just 4 points. ( orig using rubber adhesive pads)i think i used silicone to put it back on before.

[Yamamaya42]

https://imgur.com/TabuvnS
https://imgur.com/yV4aYz2

this is what I hate about the yolk assembly on this

it WAS stuck to the CRT bell via rubber pads at 4 points, that I'm sure would have fallen off by now, because the glue on them has long ago turned gummy and lost it's stick. those 4 points was the only thing holding it on aside from being on the neck.

I guess i can silicon it directly on w/o the rubber pads, as the missing thickness of them won't matter that much, and there is enough adjustment in the yolk assembly to make up for it. i mean its hardly 1/16th of an inch thick pad.

[Electronic M]

Originally Posted by Yamamaya42

https://imgur.com/TabuvnS
https://imgur.com/yV4aYz2

this is what I hate about the yolk assembly on this

it WAS stuck to the CRT bell via rubber pads at 4 points, that I'm sure would have fallen off by now, because the glue on them has long ago turned gummy and lost it's stick. those 4 points was the only thing holding it on aside from being on the neck.

I guess i can silicon it directly on w/o the rubber pads, as the missing thickness of them won't matter that much, and there is enough adjustment in the yolk assembly to make up for it. i mean its hardly 1/16th of an inch thick pad.

Couple of notes:
They make 1/16" high strength double stick tape and you can get it at hardware stores....I use the stuff doubled up as a position locking spacer when I reattach the safety glass on CRTs I've done a cataract removal on. I lay down 4 1" strips at the center of each side edge of the face then caulk the whole edge. Some replacement CRTs have the double stick pads on them right out of the box.

Two: unless the CRT is being replaced the metal bracket is not meant to come off the CRT. To remove just the yoke undo the side wing nuts.

[Yamamaya42]

When I replaced the CRT in the 90s, the original tape tabs had already degraded into a gummy gooey mess, and were hardly sticking any more, which I put back on with silicone (using old orig pads).

That seemed to work well, until last year after being in storage for many years, and I tried to remove it again to try and find a tube #, I found that the pads has degraded even more, and came off very easily.

Now I still have the double stick tape I used on my 21fjp22a, it's not super high strength, but should hold long enough for me to re-enforce it with fresh silicone.


And yes, some fool broke the red pin socket guide off when they were in the shed one day.
very annoyed at that.

[Yamamaya42]

something tells me that when this sets, it wont be coming off that easy :p

https://imgur.com/NuZ9IHN

[Yamamaya42]

this was almost too easy.

yoke now bonded and 1st pass of convergence. ( will do another finer setup )
side note convergence is always tricky for me because I an VERY nearsighted, and have glasses with thick lenses that cause chromatic aberration, it reeally plays hell when you do convergence when you have your hands on the adjustments on the back and looking at the screen through glasses at an angle. you almost have to stick contacts in to do it right.

https://imgur.com/ZFadKRr
https://imgur.com/EZxMQLi

purity and white balance is set.

I still have to run video essentials to get it all at it's best, and dust off the inside PCBs.

other than that this TV is GTG.

[Electronic M]

Several of my sets are not practical to directly view the CRT and adjust the controls so I used to use a propped up full length mirror....then I found a TV service mirror built onto an adjustable music stand and that is probably the one service tool nobody could pay me enough to sell.