I think they could do, but safe shipping would be the main problem...

And what's wrong with them? :scratch2: I've never bumped into any problems with Russian tubes, at least with vintage ones.
Anyway, they do provide a nice warranty, as well as use modern brand-new cathodes with 10000-hour lifetime.

P.S. If you'd like to discuss the quality, let's get started with a random example: 2A3 RCA vs 2S4S Svetlana

Hence the reason why the traps used to be called beam benders by techs or engineers. This is a good thread, but I'm still left with a question that's been in my mind for many years, but never really needed answering as I never burned a tube. The procedure I have always used (I forget now where I learned it) is to set brightness to a mid level with the magnet in approximately the correct position (over the split/gap in the gun) and rotate for max brightness. Then move slightly back and forth again for max brightness. Sometimes corner shadows require retouching of the magnet. I assume that maladjustments that produce burn must be if the magnet is adjusted for anything but max brightness. I never have taken a chance on that and always work fast when setting one.

Here's another interesting topic that I don't believe is covered here. What about the double ion trap magnets. A crt such as a 10BP4 calls for one. I have an RCA 8T 243 (that I am trying to get rid of) that I got with a 10BP4 and it had a single trap. It did produce a raster, but reading data on the set and the tube told me that it needed this double magnet, so I found one thanks to the Internet and possibly this site. Before the WWW, it would be almost impossible to find such an item. Anyway, it's still there and I never finished the set's slated restoration. I think I will snag the trap when I find a home for it. I will of course inform the new owner who will still be getting a heck of a deal.:thmbsp: Point being, I never knew and still don't know what the double magnet does that a single doesn't and why some tubes call for one and not the other specifically. I bet there are a bunch of BP4 owners here that are running on a single trap with no problem.

This is an interesting thread, I hadn't thought much about it.
Whether the gun needs a double magnet probably just depends on the gun design. Its also possible the if the tube is rebuilt it might not have the original gun design. Seems like there were many types of gun designs. The people that designed the guns must have understood how the ion traps worked, some of that info must have been lost.
Probably a lot of experimentation. 'Beam bender' does seem a more accurate term.
Whether the 'burn' on a crt is made by ions and just were they come from to do the damage is a good question.

I've had issues with Russian tubes, and they have a very low reputation among most audiophiles and antique radio restorers. Even the terrible Chinese tubes seem to be better. I'll wait for rebuilding to get off the ground at the ETF...

Yes, it depends on the gun design. The two basic types and bent gun and slant cut. As near as I can make out, the bent gun uses a single magnet and the slant cut uses a dual trap.

I agree with what notimetolooz posted earlier. You're not going to cause ion burn by a misaligned trap but you can damage the gun elements with the electron beam.

Here's a diagram of how the double magnet type works.
https://c1.staticflickr.com/3/2808/3...69046747_o.png

That works properly only if the magnet keeps its initial power. Howewer, Al-Ni-Co magnets are often degaussed from aging. A degaussed magnet seems to behave properly while aligning, i.e. it still provides some "max brightness" position, but this does not mean that the whole electron beam reaches the screen.

I have at least one reverse example with a bent-gun picture tube, but it could happen from a degaussed magnet as well.

They just have to be well-chosen. There are some top-grade ones (Svetlana, MELZ - just look at the pictures I attached to the previous post), some normal "workhorses", and, as always, some crappy crap hurting the whole reputation. I'm guessing that I should write some sort of choose guide here.

I have always tried to keep the ion trap with the set it came with. My highest hour is a Motorola with a 12lp4 (can't remember the chassis but I think it is either made in 1949 or 1950. Original tube as far as I can see. Good and clear, no burn and many(!) run hours! My TS-4J takes a bit to get bright but looks good after about 10 minutes.
As for Russian tubes, my worst fire breather is a Audio Research D-150 (1976). I use Svetlana 6550B types in regulator and output. This critter will kill a set of GE welded plates in about 2000 hours. I've had the Svetlana going on 3000 hours (close to needing a change according to ARC) but no sparks/blown $11.00 dollar fuses in a long time. I have heard the "C" types are better but I'll wait till it no longer meets specs to change anything. I also have the Svet "B" types in my D-115. The D-115 laughs at Chinese tubes! Then eats them!

LOL, we forgot to talk about the sets that left a single spot at dead center of the crt for a few minutes after the set was turned off. I have heard that those crts can show a burn, but I'm sure it would be after many years of service. And the only sets I've ever seen that do this are 60s sets which means that it has nothing to do with ion traps as they were gone the way of the Edsel by that point in time.

Point being I guess that not just ions can destroy the phosphor of a crt. Any type of concentration of the electron beam over a long duration will burn into the tube. That's why we turn down the brightness if working with a set that has lost vertical or horizontal deflection. I made the mistake of not doing that years ago and ended up with a perfectly performing set with a beautiful line burned into the crt.

I had an aluminized CRT in a 59' Zenith with the power-off spot burn hole in the phosphor...I found a better tube in the last year and dumped the working one with the spot off on someone.

I had a really nice 59 Zenith Space Command floor model with the 24" tube. I tried and tried to find a home for it. Never could; not even free. I wound up saving the chassis and the remote stuff and busting up the rest. I hate is so bad when that has to happen. It would have made someone a real nice daily watcher as there was almost no hours of use on it. I say that as the chassis was only lightly dusted with all factory Zenith tubes. The crt was super bright and crisp. Man, I better shut up or people are going to want to kick my butt! LOL. It's what happens when ya bring a woman into the home. Now shes gone and it's gone, but there's now room for me to work on my Zenith "roundie"!!!!

If ya still have the thing, I have all sorts of parts.

I've been thinking about buying the tuner and space command hardware off of you to upgrade mine to space command (it has the bezel microphone and chassis shelf space for space command but was not equipped) for a few years. It might finally be time for me to pull the trigger after the ETF.

Had one of those years ago. Mine was a vertical chassis console. I hate vertical chassis sets :/

"Ion burns" on tubes without straight guns are not in fact "ion burns" in the sense some people still seem to believe:

http://www.videokarma.org/showpost.p...20&postcount=8

http://antiqueradios.com/forums/view...16871&start=40

Thank you Kevin!

Well that's interesting reading.
In that case the burn on my 12JP4 is an Ion burn because it has a straight gun, but the spot on the 8AP4 would be from vaporized metal from the gun.

I once had a 17" bent gun CRT from a Setchell Carlson (This one in fact http://www.vintagetvsets.com/setchell.htm) that had several flea bites on the inside of the screen that looked like micrometeorites had stuck the phosphor and blasted it off.

These weren't large fuzzy spots but more like how a windshield gets pitted when a small stone hits it, only the Phosphor was affected though, not the glass itself.

Possibly the beam had hit the screen when there was no sweep but these were off to the the side, not dead center.

Also note that WeekendHacker's analysis of ion deflection/ion burn size is incorrect. An ion is NOT deflected by 10% of the deflection angle the electron beam undergoes. He's completely missing the fact that the ions in a magnetic focus tube are NOT being focused before undergoing the minute degree of deflection they experience. Well, they are being focused, but again, the magnetic field has such a minute effect on the ions, that they are essentially unfocused in comparison with the electron beam. If you had a 'static focus tube like a 12AP4 or a 9AP4, you should see a MUCH smaller ion burn because the ions are focused along with the electron beam, and then deflected to a marginal degree by the magnetic field. The ion burn on a 12JP4 is comparatively large because the ions are essentially unfocused. The large burn is NOT a product of deflection; his assertion that the ions are undergoing 10% of the deflection experienced by an electron is absolute hogwash.

Does anyone have a photo of a 12AP4 or 9AP4 with a really bad ion burn?

Edit again:

The issue of focus is actually what has prevented fast neutron beam therapy from taking off. For certain tumors, especially tumors that are extremely hypoxic, neutron beams do more damage to the rogue DNA than proton beams, X-ray photons, etc. There's a problem with a neutron though: they are both relatively massive, and chargeless (well it may have a charge around 10^-22 e, so essentially chargeless). Because they are changeless, we can't focus them electro-statically or magnetically, so we must resort to collimating a "beam" from the neutrons produced. This is incredibly inefficient, and shaping the beam can be a bit of a challenge. The ion beam in a magnetic focus, magnetic deflection tube is analogous in some respects to a neutron beam: you'd better produce it with the direction you prefer, because you can't do anything to deflect/focus it later.

If I'm not mistaken WH retracted that notion in his last response.

OK, just let me know in a PM. I will make you a decent deal on the stuff. Like the set was; the parts are in immaculate condition. It's so hard to keep track of everyone. I am thinking that you may have some items worth making a trade on. I'm pretty much into nice vintage radios, meaning I'm getting few if any plain AA5s. 6 tube jobs with power transformers from the 30s and 40s are about the best of radios.

Also, I am into vintage test equipment, but I'm getting quite the pile of that stuff. My big wish is a black face Hickok 209A. Anything Hickok is worth consideration. I need a meter movement for a 209C which seems to be some rare bird.

The 12QP4 on my Hoffman 601 apparently has a ion burn spot and I'm trying to make sure it doesn't get worse (not too noticeable when images are moving on the screen and probably even less with the easy vision screen in front of it)

Looking in the Riders, the instruction for "beam Bender" adjustment are confusing. It says to point the arrow forward, toward the 2nd anode and away 180°! I have no clue what this contradictory statement means. Does that mean point the arrow toward the 2nd Anode and then rotate the trap 180°?

I just adjusted it for maximum brightness. Seams like that would be sufficient?

https://i.ibb.co/fQCmqYn/A18-BFF18-2...-C3-EA7-EC.jpg
https://i.ibb.co/FWSmZ20/D2-B4952-F-...9399-FD4-A.jpg

https://youtu.be/bKE7tG01_xo

My bakelite and wooden 49-701 and 702 7" Philco's both have the same mild ion burn. It's suprising because I never saw it on a 7" model before. The only other set I ever had with it is a Dumont "doghouse", but it's common with them. The burn is hardly noticeable watching something and hardly distracting. I figure if I was 70+ years old I'd have some dark spots too! :)

Forward meaning the arrow is pointing towards the face of the CRT. Rotate the trap magnet around the neck so magnet is on the opposite side of the anode cap.

I think thats more or less where it landed for the brightest picture.

If you find a set with X burned into the screen that's from a pirate who left the treasure map with x marks the spot up on the screen for too long

In extreme cases the glass can even be melted!

Peter :yikes:

Arg , don't ya go be givin the landlubbers all our pirate booty secrets ......

:D

Redefining a glass nipple. ;)

:lmao::lmao::lmao:

:lmao::lmao::lmao:

Peter is that a CRT you own or a picture you found? To me that looks like a metal anode connection rather than melted glass. If the glass melted the vacuum would suck it in not bulge it out. I may be wrong but I think that is a test pattern tube...I forget the exact name they had but I've read they had broadcast test pattern generators tubes in the 50s that were basically a CRT with a permanent pattern built in and that they had the second anode connection in the center of the screen because the black spot in the center of the common US indian head test pattern would be there.

Monoscope.

https://encrypted-tbn0.gstatic.com/i...tM9zg&usqp=CAU

Also some WWII radar CRTs (3DP1) I think that's what he's showing above.
https://encrypted-tbn0.gstatic.com/i...egkDA&usqp=CAU

Yes, it is a tube I have with an electrode to generate polar displays as in Banderson's post above.
http://www.r-type.org/exhib/abo0197.htm

Peter.

Indeed, interesting technology.

https://www.oscilloscopemuseum.com/u...e_ts100-ap.pdf

https://www.oscilloscopemuseum.com/o...-ap-s604c.html

jr

Very cool. I have one and build a circuit from scratch to generate the circle but not much else. That's the first I've seen of the actual equipment that used them. Lots of tubes in there to generate the sine and cosine waves for the deflection plates.