I just had the find of the year! I saw this Sony Indextron on eBay, and never thought in a million years I'd win it for what I bid... I DID!!!!! :banana:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=310125196063

Then, I had a lot of trouble believing that the set could actually still be in working order, as there are only a couple of them known to exist still working. I got it today, and it is indeed brand-new. As any of us Sony enthusiasts know, the gray plastic finish around the control buttons gets shiny almost right away with any use. Not on this set! The factory kinks are still in the AC adaptor cord too. I gingerly plugged it in, and pressed the POWER button...... In a couple seconds, it came to life! It's such a weird picture in that if you blink, you see either all red, all green, or all blue. That's because of the fact that it's the Indextron, and not a standard color tube. (the tech aspects of the Indextron tube were discussed by other AKers in another thread).

This was a GREAT birthday present to myself!!!!!!!

Charles
http://i104.photobucket.com/albums/m174/kx250racer/SonyIndextron.jpg

http://i104.photobucket.com/albums/m174/kx250racer/SonyIndextronBox.jpg

http://i104.photobucket.com/albums/m174/kx250racer/SonyIndextronPic.jpg

http://i104.photobucket.com/albums/m174/kx250racer/SonyIndextronTag.jpg

http://i104.photobucket.com/albums/m174/kx250racer/SonyIndextronTop.jpg

that is way cool, Charles! It's such a rarity to see one working, especially in such wonderful condition with box and paperwork!

Congratulations!

Awrite, Charles ! What is the deal w/these things ? Why do they NOT want to work ? Izzit something to do w/the funky CRT, or something else ?

wow, so what would something like this in this condition normally go for? I never knew there was such a big collectability for the indextron. It looks like it was literally bought from the factory yesterday. Congrats!

Cool thing, don't see those too often, let alone working ones. Enjoy yours!

Neat! Works great, huh? Never had the pleasure of owning one. Happy birthday, BTW!

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I would open it up and check for leaking caps before you run it too much. Every single one I've seen the inside of (including working ones) has been FULL of puking electrolytics.

That's good advice... I remember the Mitsubishi Picture-In-Picture module fiasco with the leaky electrolytics and eroded traces... This set DOES have the same telltale urine odor, which tells me indeed there are leaky caps. I bet the caps that Sony and Mitsubishi bought came from the same place. Same years, appx.

I don't know why these sets are considered so amazing when they are still working.

I think it's like a Cadillac Diesel from the early 80s... They're known not to run; never did run for more than a few thousand miles on each new engine, and when one comes clattering down the street in 2009, everybody's jaws drop :music:

wow, so what would something like this in this condition normally go for? I never knew there was such a big collectability for the indextron. It looks like it was literally bought from the factory yesterday. Congrats!

Thanks! I can't be sure on today's value, but I sold one in very clean shape, not working, but it did have the original box, about 8 years ago for a similar price to this one. The last working one, I recall, went for over $500. But with the economy, I'm sure these, and all other collectible TVs, have cooled off. Part of the mystique is that I believe I read that Sony cancelled the warranty on these, and offered a buyback. So I bet most of them went back to Sony.

Charles

(OFF TOPIC)
I do not know about the Indextron, but I can tell you stories about the GM diesels from the early 1980s. Both may father-in-law and a co-worker of mine had one. One had immaculate care, while the other was abused. Both engines threw rods at between 45 and 50 thousand miles.

...

It's such a weird picture in that if you blink, you see either all red, all green, or all blue. That's because of the fact that it's the Indextron, and not a standard color tube. (the tech aspects of the Indextron tube were discussed by other AKers in another thread).


I don't understand this part, because elsewhere it says the colors were switched as the beam scanned across the stripes, which would be much too fast for eye-blinks to catch only one color.

Anyone got an idea on this?

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To save some search time...the Indextron tube is a straight-line stripe from top to bottom with a black guard band in-between each stripe. No shadow mask or wire mask. Just a RGB switched color beam going to it's matching color stripe.

Black/Red/Black/Blue/Black/Green and so on. It knows where it is by sensing the green stripe from the rear of the tube. Thus the indexing. This set actually has a few stripes ahead of the viewing area to get it up to speed and keep it synchronized.

See Chuck A's site for the history of this concept in the Philco Apple tube. Sony ended up with the rights to the concept and this is what they did.

It ain't Linytron or Trinitron.

The black guard band prevents the previous switched color beam from contaminating the next color stripe during the color switch in the guard band. And focus is critical. If the beam spot focus is too big, it leaks across the guard band and contaminates the next stripe before the switch. Red beam in to green stripe, etc. It looks just like a degaussing problem.

If you count the guard band as a pixel, you have a six-wide pixel with no next line stagger for the traditional triad. Double the normal triad RGB pixels and now half the resolution with the color stripes easily visible.

And now that you have a black guard band after every RGB stripe, you have 1/2 of your screen in black. That is assuming that the guard band is as wide as the color stripe. I suspect smaller but that does nothing for brightness and contrast.

All said, I cannot think of any variation of analog tv like this that actually worked other than color wheels. Therein lies the rarity and collectability.

And my Indextron, restored by Andy, will be the set I watch the sunset of analog on.

Dave A

I would open it up and check for leaking caps before you run it too much. Every single one I've seen the inside of (including working ones) has been FULL of puking electrolytics.

I don't know why these sets are considered so amazing when they are still working. I've personally worked on 5 or 6, and all of them just needed a basic re-cap plus some board clean up. I had to fix one open circuit board trace on one of them. I've heard of one set than needed a hard to find IC because some of the pins had corroded away, but that's the exception.
Wow, nice find. I paid like almost $800 for it used.

Andy fixed mines and I agree with him. Even though it's brand new, it reserves the right to leak caps without warning.

The leaky caps can short and blow the unobtainable ASIC that controls the tube...

I agree, time to be proactive and recap the thing.

I agree on the precautionary re-capping... I'll refrain from turning it on until I recap it. I probably got lucky not to blow it up by powering it on the one time for the pictures... I'm glad I quit while still ahead!

And a note on the color fields... I can't explain it either, but also, when I took the photos, I had to take about 25 photos of the screen until I found one that had all 3 colors. Most were either one color, or two with a black band. I also can't hear the horizontal oscillator, which I can hear plainly on most other TVs. I found that strange too....

Charles

It amazes me what these go for. Nice find by the way! You couldn't have found a nicer one. Is the leaking cap problem what makes them so rare? Or, did they not make many? Or both? I would love to have one but the price always scares me away. Maybe I'll get lucky at an estate sale or something.

Probably both if you ask me, Mark. These had to be very pricey when they were new! Bet few people would shell over much coin for a portable back then. :scratch2:

Can't explain the technology employed in the set but what's interesting is that you can't hear the horizontal oscillator whine, Charles...Makes me think there's some type of unusual configuration used there which may just explain the unique technology of the tube (?)

Glad you got it, I'm sure it will be in good hands...

Hello Charles,

Congratulations on the Indextron, & Welcome! to the club of Beam-Index CRT users.

I have the unobtainium full Indextron service manual and schematics. In your mailbox ASAP if you want it.

A few pictures:
- Dead caps, Andy's picture (Thanks!) all the purple ones leak
- Caps changed on ONE of my Indextrons, SAME quantity on unit #2.
- The Indextron CRT seen from the gun side. Note how simple the gun structure
appears.
- Rear view of the KVX-370, open.
- ONE Gun = PERFECT convergence! *

*see this pix & more here:

http://audiokarma.org/forums/showthread.php?t=120906

Best Regards

jhalphen
Paris/France

Thank you for the pics, Jerome! I haven't taken this one apart. But I just got a rock in my stomach: I remember seeing someone selling 2 Sony small tubes on eBay; of which was supposedly color, but I thought they were both 4" B&W tubes by the photo in the ad. Now looking at you pics, I know what the "color" one was an Indextron :( It sold for $9 new in the box.

Your photo of the leaky caps is encouraging... Not so many as I was imagining, and they're thru-hole!!!!! I pictured about 50 surface-mount caps to be replaced. I'll go at it sooner than later :)

Charles

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Hi to All,

Charles: i sent you the complete Indextron service data yesterday.

Here is a drawing depicting the screen structure of a Beam-Index CRT. This is not the Sony Indextron, but a CRT using similar technology.

Best Regards

jhalphen
Paris/France

Thank you Jerome for those!!!! I received them, and will print them out. I especially liked being able to better-understand the indexed scan theory!

Charles

To save some search time...the Indextron tube is a straight-line stripe from top to bottom with a black guard band in-between each stripe. No shadow mask or wire mask. Just a RGB switched color beam going to it's matching color stripe.

Black/Red/Black/Blue/Black/Green and so on. It knows where it is by sensing the green stripe from the rear of the tube.

One big problem with this scheme is that you could not allow the tube to have deep blacks in the picture. Else the indexing looses track of which stripe the electron beam will be hitting when the video image scans out of a black region in the picture. Thus a lower limit on darkness, and the picture looks washed out, kinda like older LCD displays where the LCD pixels couldn't block all of the backlight from getting thru in black areas of the picture.

It did get rid of that PITA convergence chore in manufacturing. Which would cut manufacturing costs.

The width of the stripes on your Indextron reminds me of the coarseness of some GE Portacolor CRTs.

The width of the stripes on your Indextron reminds me of the coarseness of some GE Portacolor CRTs.


You're not kidding!

Charles

If the indextron tube is used with a OLCI or deep tinted glass faceplate, the black level issue can be resolved at the cost of overall intensity.

If the indextron tube is used with a OLCI or deep tinted glass faceplate, the black level issue can be resolved at the cost of overall intensity.

Actually, no -the minimum beam current is a certain fraction of the maximum, and that ratio sets the contrast ratio. Darkening the faceplate darkens both highlights and lowlights and keeps the ratio the same in this case. A dark faceplate does imrove poor contrast due to reflection of room light, since it darkens the reflected light twice (light going in and reflection coming back out), while darkening the highlights only once (light coming out).

Actually, no -the minimum beam current is a certain fraction of the maximum, and that ratio sets the contrast ratio. Darkening the faceplate darkens both highlights and lowlights and keeps the ratio the same in this case. A dark faceplate does imrove poor contrast due to reflection of room light, since it darkens the reflected light twice (light going in and reflection coming back out), while darkening the highlights only once (light coming out).


Where the issue is here is the Indextron needs a minimum amount of beam current to excite the index phosphor, to provide the feedback to the color switching circuit, keeping the timing in lock. This made the image appear as if the brightness was too high since it also illuminated the other phosphors as well.

In the very few industrial aviation indextron displays I saw, they placed OLCI glass in the front of the tube face to darken the background, since the high black level would be a nuisance to the pilots in the aircraft. This had the net effect of as you say cutting the maximum brightness, but the OLCI coating on the glass prevented the glare from sunlight from washing out the picture so it was a favorable tradeoff.

These little sets were really pricey when they were new. I remember it was a toss up between one of these, a 8" or a 19" at >$500.

Good Day, Gentlemen,

Genuine Sony KVX-370 Indextron screen pictures.

Judge for yourself the picture quality...

Courtesy John Folsom Jr (FLA), 2008 - Thank You! John

I have 3 IndexTrons, operating in Europe via NTSC --> PAL Standards Converter, i can confirm obtaining same pix quality.

Best Regards

* Some units repaired by Andy, TX, Thank You! Andy

jhalphen
Paris/France