'70 Zenith 12" tube type B&W

[Jeffhs]

Originally Posted by OvenMaster

. When the picture started to have the CBS eye look like an egg, I tossed it.

Tom

You didn't necessarily have to discard that TV if it had vertical height and linearity controls on the back (if I remember the layout of my own 1978 Zenith). If yours had a vertical oscillator and output tube, a replacement should have cured the problem. However, if the tube was one of those oddballs they don't make anymore, and with vacuum tubes being so difficult to find these days, or if the problem with the set was caused by a chassis fault such as an off-value resistor or capacitor, it wouldn't be worth trying to repair. Today, a TV repair shop (what few of them are left) will charge an arm and a leg just to look at the set; the repair charges (parts, labor, overhead, etc.) on top of that could be high as well. I once took my Aiwa bookshelf stereo system in to a local TV repair shop for repair of a problem with the cassette decks. The estimate for repairs was $175. I got the unit back from them the next day, not wanting to spend that much money on a stereo system that was already obsolete (my system was already six or seven years old at the time). I would not dream of spending any more money on this system today, as it is now nine years old and definitely not worth repairing. I bought a used stereo cassette deck a few months later (after the decks in the stereo quit completely) and patched it into the system. Works great. I don't use it much except to transfer cassettes to CDs, but it does what I want it to do. I only paid $20 for the deck (got it from John Kendall's Vintage Electronics: http://www.vintage-electronics.com), which beats paying $175 to have the stereo's internal decks repaired.

[jfrog1983]

I also got one exactly like this, missing the power cord and there's a big hole in the back cover, but it works just fine!

I wonder where I can find more of those interlock type cords...

[zenith2134]

jfrog, go to a TV repair shop and ask about the cord. They'll have a bunch I'm sure.

[radiotvnut]

Or any old electronics supply house. I think www.tubesandmore.com has them; but, check with the TV shop first. They may just give you one as these have not been used on TV's in close to 30 years.

[bgadow]

Remember that some are polarized; good chance this one is. At the set end, one hole will be bigger. I have at least one of these in the stash, Taiwan though, I think.

[peverett]

I have a couple of comments.

1. Most vacuum tubes (especially small TV tubes) are not hard to get. Antique Electronics Supply (and others) carry them. You may also be able to find them at hamfests, etc. There are few oddballs(eye tubes for radios, 1L6 tubes for Zenith radios, etc.) that are difficult to get. Also certain audio tubes command a high price. However, in general, TV vacuum tubes are very easy to find, much easier than some of the integrated circuits used in later TVs. Some of the integrated circuits are unobtainium now.

2. I have found that on some radios that I have restored that even plain water will remove numbers from some dials. Be very carefull when cleaning.

[radiotvnut]

Originally Posted by peverett

I have a couple of comments.

1. Most vacuum tubes (especially small TV tubes) are not hard to get. Antique Electronics Supply (and others) carry them. You may also be able to find them at hamfests, etc. There are few oddballs(eye tubes for radios, 1L6 tubes for Zenith radios, etc.) that are difficult to get. Also certain audio tubes command a high price. However, in general, TV vacuum tubes are very easy to find, much easier than some of the integrated circuits used in later TVs. Some of the integrated circuits are unobtainium now.

2. I have found that on some radios that I have restored that even plain water will remove numbers from some dials. Be very carefull when cleaning.

That's right. They usually can't give most TV tubes away. Especially the oddball filament voltage tubes used in series string sets. The only exception is most color TV horizontal output tubes. It seems like those go up drastically every year. You can thank CB'er's and HAM's for that, as these tubes are used in RF amplifiers. I wonder when the Russians and the Chinese are going to get on the horizontal output tube bandwagon? I'm sure they could make some money if they started making HO tubes, as well as some of the hard to find radio tubes.

[Eric H]

Originally Posted by radiotvnut

Or any old electronics supply house. I think www.tubesandmore.com has them; but, check with the TV shop first. They may just give you one as these have not been used on TV's in close to 30 years.

I just bought a few of them to have on hand, they ain't what they used to be, very stiff and hard compared to the older ones and difficult to stretch over the original mounting rivets.

Well, what can you expect for $1.25 I guess.

They were non polarized BTW.

[Kiwick]

Originally Posted by radiotvnut

I wonder when the Russians and the Chinese are going to get on the horizontal output tube bandwagon? I'm sure they could make some money if they started making HO tubes.

The Chinese are already making 6DQ6, PL36, PL500, PL504 and PL509 tubes for HAM radio RF amps, but in my experience they're poorly made and they don't hold up well if used in TV deflection circuits which are a lot harder on output tubes than RF amps, especially European sets with 110 degree CRTs which need a horrible amount of power for their deflection circuits.

I've once bought a brand new Chinese PL36 on Ebay for a 1964 Phonola set, as the original one was tired and produced a narrow raster, the Chinese tube worked fine with a full width raster for a few hours then it shorted H/C, luckily the breaker tripped before wiping out something else in the set.

I then replaced it with a Telefunken PL36 from a junked CCTV monitor and it worked fine.