Anyone know what causes this?
 

On many of my b&w sets, there is a verticle line on the left side of the screen. Usually, I only see it between scenes. It's not really noticeable if there's a picture on the screen.

The screen shot below is on my Philco Diamond D set. I also see the same line on my b&w '63 Curtis Mathes, '72 Zenith, '58 Magnavox, and '59 Predicta. Doesn't seem to matter what source I'm using... cable, DVD, air... it's still there.

I've never noticed this on my color sets... just the b&w ones.

This doesn't really bother me... like I said... it's really only noticeable between scenes. Since I have a handfull of sets doing this, I thought maybe someone else might have experienced this as well... and found its remedy???

Note: Don't pay attention to the horz line at the bottom and other wavy lines... those are cause by the digital camera.

Open ground in your CATV system... Very very common. You are probably seeing the signal from your cable box/VCR/DVD, plus a weak piggyback of a local TV station. This causes your exact symptom when you say it's the same on more than one TV.

Is your Cable Box, VCR or DVD set to output on a channel that is a receivable TV channel? BINGO That will cause your line. If both Ch 3 & 4 are channels with local signal being broacast, only relief would be to convert the 300 ohm flat wire that is inside each TV between the ant terminals and the tuner, over to shielded cable. Or you could try wrapping the wire with foil and grounding it, but that might also cause other ghost problems.

Charles

Good thought, but line shows up regardless of source. The set in the pic above is running on rabbit ears... not cable. It creates the line with any source... cable, DVD, rabbit ears.

On the other hand, I did as you mentioned (turning to an unused channel) and there is no line.

I've noticed that my '59 Motorola b&w set DOES NOT show this line. So, I would think the problem would be within the sets that do show the line.

Strange thing is... I usually only notice this on vintage b&w sets... not vintage color sets.

Try adjusting the horizontal drive and see if it has any affect.

I notice it too on my vintage black and white sets. Fine tuning helps minimize it but it can still be seen sometimes. It is not a signal source problem as I don't have cable in my house, just rabbit ears on all sets.

I suspect it is coming from the horizontal curcuit, some kind of ringing maybe? I think it is just a design characteristic of b&w sets since the horizontal sections don't need to be as sophisticated as in a color set.

It's like an allergy. You just have to learn to live with it.

I think it is the color information. In the old days the station would turn that off when showing a b&w show. But now they leave it on all the time.
Ed

Ghosts.

Remove a video IF tube and see if it is still there. If so, it is coming from the horizontal circuit. It should not be there in the Philco Diamond D. It could be the result of a mismatched yoke and/or flyback if either has been replaced. Make sure they are original parts.

Then check the horizontal oscillator and coupling circuit.

Don

Thanks for the ideas, guys. I'll try them in a few days on the Philco when I get back to my cabin (where the Philco is). Later today, I'll be poking around in my 15 and check the stuff that was mentioned last week for that set.

Thanks again!

Looks like a good ole drive line. Turn down the h drive and it should go away.

Looks like Barkhausen interference (aka snippets) to me. My 1970's tech-school copy of Grob's Basic Television, covered the subject adequately (but not in the 1949 edition, though). In a nutshell, these undesired oscillations from the horizontal output tube show up as vertical lines down the left side of the raster. They are usually black. Keeping unshielded antenna lines away from the horizontal output section also helps.

Yeah, it does kinda look like Barkhausen interference, but I've never seen it look like that before. That looks more like a video signal interference than the Barkhausen interference, especially since you can only see it in light scenes or whatnot - Barkhausen interference tends to be always there, and like Einar72 said, it's typically black. Another cure for Barkhausen interference is to just swap horizontal output tubes around until you find one that doesn't oscillate.

But I'm still betting on ghosts. The dead have a way of interfereing with television reception. <grin>

-Ian

To me it looks like the horizontal deflection slowing down a little midscreen. That would cause more electrons from the beam current to accumulate per given area of the screen, and thus that area will look brighter. Supposidly adjusting the "horizontal drive" trimmer should reduce this, but I have an RCA set where I can't get rid of it. Go too far and I lose horiz sync.

I think the correct term is snivets, not snippets. They are usually black lines or splotches on the left side of the screen and are particularly bad on UHF channels. This problem looks like a drive problem to me.

My Hallicrafters T-67 had Barkhausen interference. The cure was to substitute a horizontal output tube that didn't oscillate.

It does seem odd that you'd have four sets with that identical problem, but what do I know.

One of my old TV books has a good discussion of Barkhausen. Besides subbing the tube, they suggest reducing the drive, or even putting a small circular magnet around the output tube and rotating it until the oscillation is suppressed.

I don't know if what you have is Barkhausen effect, but those are all pretty easy things to try.

P.S. Reading an adjacent section in that book, they say that simple misadjustment of the horizontal drive makes a white line (yours looks white to me), while Barkhausen creates a dark line. Which favors the drive explanation, I guess.

OK, now I'll shut up :-)

After hearing everyone's input (and thanks to all for it), I'm going with the idea that the Horz drive needs to be turned down. This is what I figured from the beginning, but was curious of what everyone here thought.

My sets that produce the white line all had new lytics and caps replaced, and likely new output tubes. I never checked or adjusted the drive in those sets. Perhaps I should have.

As mentioned before, I've never dealt with this in a color set... and I'd guess it's because I try to make sure that the drive is set correctly so not to roast a flyback.

Thanks again for the comments. I'll let you guys know what I find as soon as I pull the backs off the sets.

There is no horizontal drive adjustment on the Philco Diamond D.

Well then... that might present a problem! Oh well... glad you told me that... or I would have been pullin my hair out tryin to find it! :yikes: