Just got a 1984 RCA VJM2023S (CTC-121) chassis

[radiotvnut]

Is that hissing noise actually a high pitched squeal (somewhere in the neighborhood of 15,750 Hz)? If it is, it's probably coming from the flyback or some other coil in the horizontal circuit.

That black cut-off at the top and bottom can probably be fixed by a slight adjustment of the vertical size control.

[Blast]

Originally Posted by radiotvnut

Is that hissing noise actually a high pitched squeal (somewhere in the neighborhood of 15,750 Hz)? If it is, it's probably coming from the flyback or some other coil in the horizontal circuit.---snip---

Now, MINE does THIS (but I couldn't tell you at what intervals)! I would have never confused it with a hiss so I didn't bring it up.

If you were to have HV arcing I would think you'd see a real screwing up of the picture.
Brian

[zenithfan1]

Originally Posted by radiotvnut

Is that hissing noise actually a high pitched squeal (somewhere in the neighborhood of 15,750 Hz)? If it is, it's probably coming from the flyback or some other coil in the horizontal circuit.

That black cut-off at the top and bottom can probably be fixed by a slight adjustment of the vertical size control.

That is what mine is doing, the high pitched squeal is ANNOYING! It's the flyback.

[waltchan]

If it's the flyback, is it still available after 24 years? I think this is terrible. The TV may need to be trashed if flyback is not available.

[radiotvnut]

Originally Posted by waltchan

If it's the flyback, is it still available after 24 years? I think this is terrible. The TV may need to be trashed if flyback is not available.

I don't think so. I tried to get one about 10 years ago without any luck. You might can get a NOS one from some place like Moyer's Electronics.

[Blast]

Originally Posted by waltchan

If it's the flyback, is it still available after 24 years? I think this is terrible. The TV may need to be trashed if flyback is not available.

I don't think I'd be shopping for landfills just yet...

[wa2ise]

Originally Posted by zenithfan1

the high pitched squeal is ANNOYING! It's the flyback.

That can usually be fixed by jamming a toothpick or similar non-conductive material between the windings and the core. Sometimes some runny epoxy can be used to fill the spaces in there to lock things down so they no longer rattle at the squeal frequency.

[Jeffhs]

Originally Posted by waltchan

If it's the flyback, is it still available after 24 years? I think this is terrible. The TV may need to be trashed if flyback is not available.

Really? Just because the flyback is making noise? If the fly were shorted or otherwise defective, and the part is NLA (no longer available), I would look at old junked chassis that used the same flyback. But to trash a TV just because the flyback is bad or going bad, and not even trying to find a replacement (even if it must be a used one),IMO, isn't right at all.

I don't have much or any experience with RCA's CTC121 TV, but from what I have read here it was a very good set in its day, and it can be again. Unless the TV has been struck by lightning or some other situation that damages the set beyond repair, I'd at least try to find a used flyback.

There are ways to silence noisy flyback transformers (if the fly is not squealing because of electrical problems such as shorts, et al.) as well. I remember reading in several old TV repair books of the '60s and '70s of a method that was nearly 100 percent effective as far as silencing squealing and otherwise noisy flybacks, but unfortunately it's been so long since I read of it that I don't remember the details any longer. One thing that does come to mind, however, is to drive little wooden shims in between the flyback coils and the core; this has been known to stop the squealing, at least until a new fly can be obtained.

Are you sure it is the flyback that is actually squealing? High-pitched squealing noises in a TV set can also be caused by the horizontal oscillator running far off frequency, but not far enough off to kill the raster. Many people (myself included) cannot hear a CRT TV's horizontal oscillator in operation (15.75 kHz is just beyond the top end of the normal hearing range), but people from teenagers to those in their 20s and 30s often can, and they find it extremely annoying. I don't know how old you are, but you may fall into the 20-30 age bracket; if so, your hearing is probably sharp as a tack, extending even slightly above 15.75 kHz, and you are hearing the noise very clearly.

But I digress. My point is that there are ways to silence noisy flybacks, as I described above; trashing a TV that may otherwise be working perfectly well, simply because the flyback is making noise, makes no sense to me whatsoever. I have seen many CRT TVs on trash piles (I've rescued a few, and at one point in the early '70s my basement in my former home was half-full of old sets) that needed only new tubes or a small part to restore them to normal operation. Even today's flat-screen sets can be repaired if one cares to go to the trouble to do so (and has the skills), but the way these TVs are built, with surface-mount components, the LCD/plasma panel itself often hard-wired to the chassis, and so on, most repair shops won't touch them unless the set is under warranty, and of course DIY user servicing of these sets is out of the question.

[waltchan]

Originally Posted by Jeffhs

Really? Just because the flyback is making noise? If the fly were shorted or otherwise defective, and the part is NLA (no longer available), I would look at old junked chassis that used the same flyback. But to trash a TV just because the flyback is bad or going bad, and not even trying to find a replacement (even if it must be a used one),IMO, isn't right at all.

I don't have much or any experience with RCA's CTC121 TV, but from what I have read here it was a very good set in its day, and it can be again. Unless the TV has been struck by lightning or some other situation that damages the set beyond repair, I'd at least try to find a used flyback.

There are ways to silence noisy flyback transformers (if the fly is not squealing because of electrical problems such as shorts, et al.) as well. I remember reading in several old TV repair books of the '60s and '70s of a method that was nearly 100 percent effective as far as silencing squealing and otherwise noisy flybacks, but unfortunately it's been so long since I read of it that I don't remember the details any longer. One thing that does come to mind, however, is to drive little wooden shims in between the flyback coils and the core; this has been known to stop the squealing, at least until a new fly can be obtained.

Are you sure it is the flyback that is actually squealing? High-pitched squealing noises in a TV set can also be caused by the horizontal oscillator running far off frequency, but not far enough off to kill the raster. Many people (myself included) cannot hear a CRT TV's horizontal oscillator in operation (15.75 kHz is just beyond the top end of the normal hearing range), but people from teenagers to those in their 20s and 30s often can, and they find it extremely annoying. I don't know how old you are, but you may fall into the 20-30 age bracket; if so, your hearing is probably sharp as a tack, extending even slightly above 15.75 kHz, and you are hearing the noise very clearly.

But I digress. My point is that there are ways to silence noisy flybacks, as I described above; trashing a TV that may otherwise be working perfectly well, simply because the flyback is making noise, makes no sense to me whatsoever. I have seen many CRT TVs on trash piles (I've rescued a few, and at one point in the early '70s my basement in my former home was half-full of old sets) that needed only new tubes or a small part to restore them to normal operation. Even today's flat-screen sets can be repaired if one cares to go to the trouble to do so (and has the skills), but the way these TVs are built, with surface-mount components, the LCD/plasma panel itself often hard-wired to the chassis, and so on, most repair shops won't touch them unless the set is under warranty, and of course DIY user servicing of these sets is out of the question.

Wow, you revive a 3 year old thread. Yes, I still have this TV. It sits in my storage right now.

[rwilson]

I have enjoyed this thread as I also have a CTC-131 that I bought brand new in late 1983 for $750. It was still working fine (after resoldering the tuner) until a few years ago. During a storm a tree fell on my power drop and I lost ground to the house. The set got 220 volts on it for a while. I fixed the small transformer but I now I can't get it to power up. I still have hope.
One of the last TV's made with a real oak cabinet and of course the first stereo TV.

[DavGoodlin]

I worked at an RCA dealer when those were new. We had a console that came out of the box squealing like that. Warranty requirements usually wanted things fixed fast without spending time to find the real cause, so a new flyback was to be installed.

IIRC, a piece of fiberglass mesh reinforced tape was included with the fly. It was to be placed between the flyback bracket and the chassis rear apron where it was bolted. This was for physical isolation and squeal prevention I assume. I have an '87 Colortrack "Lyceum TV" from a HS which is similar and I'll take a look.

BTW, is that a Pre-Thomsen set?