RCA CTC-5 "Wescott" restoration

[bandersen]

One board left (chroma demodulator) plus some parts under the chassis.


Bring on the x-rays ⚡

[timmy]

Looking good , but the chassis will outlast the crt it would be nice if someone or some company would start rebuilding crts. I speak for all vintage tvs b&w and color. Got to see the first picture from that set.

[bandersen]

Chroma demodulator board is being worked on next. I'm going to be extra careful with this one due to all the transformers and coils.


I also tested all the tubes. It seems that those with white printing are originals while the red are replacements.
About 1/2 of the tubes appear to be originals and five of those were weak or dead. Two of the red were also weak.

[Videotechie]

Nice work, is that chroma board kinda toasty or just dirty?.
I would like to find another color roundy any high heat tubes definitely would swap out to ceramic sockets. It's a shame no tv shops thought about this if customers were willing to keep their sets long term.

[bandersen]

I count about 22 potentiometers and 7 adjustable coils along the front of the chassis. Most are for dynamic convergence I believe.
This should be fun!

[Penthode]

On my CTC5, the static convergence pots had a crack at the tap in the carbon track. I think Wayne had the same on his CTC5.

My solution was to visit an auto parts store and buy a can of conductive paint used for fixing car rear window heating element traces.

I applied the paint at where the pot element tapcrack was and after 12 years it is still working fine.

[bandersen]

Thanks for the tip. After cleaning with DeOxit F5, some of them still sound crusty when rotated.

[ronl]

I havent seen this view of the chassis in years!This brings back memories of my first convergence attempt with this chassis.I was 12 years old and with some advice from the tv shop I hung out at,I got it reasonably good!A few years later,one of the convergence pots failed and I bought a replacement. Still have the new pot.Have not installed it yet. RonL

[ronl]

I just remembered what the failed convergence pot was for. blue lateral adjustment.my chassis has a electro magnet on the Crt neck for that function.it took me a few years to find the service info with that coil included.Does your chassis have a permanent magnet on the Crt neck for blue lateral adjustment? It looks like you have a blue lateral adjustment pot so that would mean you have a blue lateral.electromagnet as well?RonL

[Electronic M]

Originally Posted by ronl

I just remembered what the failed convergence pot was for. blue lateral adjustment.my chassis has a electro magnet on the Crt neck for that function.it took me a few years to find the service info with that coil included.Does your chassis have a permanent magnet on the Crt neck for blue lateral adjustment? It looks like you have a blue lateral adjustment pot so that would mean you have a blue lateral.electromagnet as well?RonL

I've had 2 table model CTC-5 sets. One with electromagnetic blue lateral, the other with permanent magnet blue lateral. The one with permanent magnet lateral had a IIRC screen pot in the location that the electromagnetic lateral set had the lateral pot.

[bandersen]

I finally wrapped up work on the chassis and replaced a few bad tubes.




I used all RCA branded tubes.


I quickly noted a few tubes were not lighting up. One of the 5U4s died and a couple of the PCBs were not making good ground contact.

Once that was sorted out, I was able to receive clear audio through the tuner.


Time to put it in the cabinet and makes some x-rays.
That gizmo on the right side monitors the horizontal output tube current.


I was first treated to a pulsating out of focus image and some high pitched ringing.


I realized this set was really loading down my variac and turned it up to get about 117 going in.
Image got brighter and more focused. HOT current at about 150mA


Feeding a color bar test pattern resulted in this. Hor. frequency was way off.


Needed to go about 7 full rotations on the hor. frequency control.
Set is much happier now. No more ringing and the image is sharper.


Convergence needs a bit of work ��

[bandersen]

Adjusted the DC bias and screen settings by eye for a big improvement


and then I tried adjusting the vertical centering, heard a pop and it's dead :shock:
I hear it's likely to be tin whiskers and the main fuse popped.

[bandersen]

This is the vertical centering control I touched when the set died.


No tin whiskers visible inside, but I did get erratic readings when I rotate while measuring resistance. Some DeOxit seems to have taken care of it.



It was F103 - a 3/4 amp fuse that popped.
I had to order some Littlefuse N-3/4 type fuses.
Meanwhile, I replaced the original 1V2 and 3A3 tubes with NOS.
We will resume when the fuses arrive.

[bandersen]

Damn. Should have ordered short 'C' types, not 'N' types.


Meanwhile, I went hunting and found the missing brightness knob.




Will have to wait another week for the right fuses.

[electronjohn]

Pooch looks as disappointed as you are