Rca ctc-63 hybrid with a weird video issue

[Turle]

So recently came across a late model rca color hybrid, the chassis is a ctc-63, which is a lot like the ctc-53 but it uses a HV tripler.

Anyway it has the weirdest issue. When it starts up it works fine, has plenty of contrast, but after about 10 seconds it just disappears into a terrible dim and low contrast picture. IMG_6173.jpegIMG_6175.jpeg even weirder is the fact that when power is removed, for the split second when the picture shrinks, the video comes back completely.

I also noticed I get a video signal again when I turn the horizontal frequency way down

IMG_6176.jpeg


Some things I’ve already checked

> all my voltages are good

> power supply is good

> no shorted transistors or diodes


I cannot figure out what it could possibly be.
Has anyone experienced a similar issue? Anything helps

[damen]

RCA used several different high voltage protection circuits in the CTC63 chassis. Excessive high voltage caused by a defective VDR near the Horizontal output tube is the most common cause. If the VDR has gold colored end caps it's probably bad. Using a variac, or turning the horizontal hold control lowers the high voltage and that's why the picture comes back.

[Turle]

Originally Posted by damen

RCA used several different high voltage protection circuits in the CTC63 chassis. Excessive high voltage caused by a defective VDR near the Horizontal output tube is the most common cause. If the VDR has gold colored end caps it's probably bad. Using a variac, or turning the horizontal hold control lowers the high voltage and that's why the picture comes back.

Interesting. I did notice when the video dies there’s a little neon indicator bulb on the chassis that lights. I’m assuming that has something to do with the HV regulation.

The vdr doesn’t have any gold colored caps but I suppose it wouldn’t hurt to check it anyway. How would I go about testing it?

[zeno]

HVSD I remember on these caused vert blinking / collapse.
That is above the CRT on a terminal strip w/ an SCR.
Other common thing IIRC was plate resistors in the horz osc.
Pix was OK but the 36MC6 had short life.
Also move one of the 5GH8's around & see if the symptoms change.
Dont trust a checker.

73 Zeno
LFOD !

[damen]

Yes, the neon light fires at a certain voltage and blanks the video. As Zeno said, the early CTC63 chassis versions did collapse the vertical instead of blanking the video. The whole idea was to force the owner of the set to have the problem repaired. This was back when everyone was told their televisions were emitting deadly X-rays. The original part number for the VDR was 133137, it was later superseded by 132995. Moyers or Talon may have them. I don't know of any reliable way to "check" a VDR other than by subbing it. Someone determined a way of crossing the always defective Zenith set VDRs to a modern replacement, but, I've not seen that for the RCA ones.

[Turle]

Originally Posted by damen

Yes, the neon light fires at a certain voltage and blanks the video. As Zeno said, the early CTC63 chassis versions did collapse the vertical instead of blanking the video. The whole idea was to force the owner of the set to have the problem repaired. This was back when everyone was told their televisions were emitting deadly X-rays. The original part number for the VDR was 133137, it was later superseded by 132995. Moyers or Talon may have them. I don't know of any reliable way to "check" a VDR other than by subbing it. Someone determined a way of crossing the always defective Zenith set VDRs to a modern replacement, but, I've not seen that for the RCA ones.

I just found 2 NOS 132995’s on eBay for a whopping $2. Will the 132995 replace a 133137?

You wouldn’t happen to have the ctc 63 schematic on you by any chance would you? Because the 53 doesn’t seem to have this video blanking HV protection circuit

[Yamamaya42]

Originally Posted by Turle

I just found 2 NOS 132995’s on eBay for a whopping $2. Will the 132995 replace a 133137?

You wouldn’t happen to have the ctc 63 schematic on you by any chance would you? Because the 53 doesn’t seem to have this video blanking HV protection circuit

SAMS folder 1362-2 $22

https://www.samswebsite.com/en/photo.../samsid/1362_2

[damen]

The 132995 is RCA's recommended replacement for the 133137. If you get two, that's even better. I used to parallel two of them when one needed replacing. The CTC-53 is very similar to the CTC-63, except for the tripler wiring and the shut down circuit. The Sams may not show your circuit because the early versions collapsed the vertical deflection. The RCA factory literature and their "Goldenrod" tips sheets explain it all. Sorry, I can't post pictures on VK or I would show it to you.

[Turle]

Originally Posted by Yamamaya42

SAMS folder 1362-2 $22

https://www.samswebsite.com/en/photo.../samsid/1362_2

Yeah I don’t really wanna buy a new schematic that’s only slightly different than the one I already paid for when I was doing a 53

[1993ctc175]

Hello there, I Have a Question About The CTC63 Model Ending

What Was Your CTC 63 Ends With ???

It Usually end with the last two letters after "CTC63"