Zenith Chromacolor Hybrid 23DC14

[zenith2134]

Regarding the 6LF6,, it isn't just the hamradio guys who want em...it's popular with the OTL (output transformerless) amp guys as well.

[Zenith26kc20]

Be sure to watch the tripler. I changed literally hundreds of them when this chassis was popular.
The first ones were blue and they would literally blow up (selenium! What a stink!) and throw tiny metal circles everywhere.
The ceramic discs siliconed to the top of the flyback on some of them like to short out also.
Futterman amplifiers and their clones love those big 6LF6 tubes! They run them HOT and mismatching the loads can bring on a expensive fireworks display!

[fsjonsey]

Originally Posted by zenith2134

Regarding the 6LF6,, it isn't just the hamradio guys who want em...it's popular with the OTL (output transformerless) amp guys as well.

Actually, it's not even Ham's or OTL guys. CB'ers are the reason 6LF6's are so rare today. The 6lf6 was commonly used in illegal CB Linear amps back in the 70's, mainly because it was a cheap and readily available sweep tube at the time.
These Linear amps were generally very poorly designed, splattered harmonics everywhere, and ran the tubes way beyond their max plate dissipation ratings. The average lifespan of a 6lf6 in one of those amps was barely in the tens of hours. And most of those amps used at least six, and some as many as 10 or 12 6LF6's, depending on output power. Back in the 70's this wasn't an issue. The 6LF6 was a common TV tube.

"Dedicated" CB'ers are still using many of these amps, and have almost completely burned through the remaining NOS stocks of 6lf6's in the past twenty or so years. They continue to pay top dollar for any NOS 6LF6 they can find, even though they could easily rewire their amps to accept the new production Russian El509/6KG6, just as the OTL amp guys have done. However, most of these guys aren't exactly the sharpest knives in the drawer, so I doubt that will happen any time soon.

[AUdubon5425]

Originally Posted by drh4683

Nice find! I'd be willing to bet a filter cap shorted out on you...The one on mine that was bad was a 2 section lytic, 100,150 @ 400vdc.

I got into the set last night and found the 2.7amp fuse blown. The electrolytic that's 150/100/15 @ 400v tested with very low resistance and didn't charge up on the ohmmeter. It also tested low with my new ESR meter. So I think you're right on the money Doug.

And Zenith26kc20, thanks for the heads up on the tripler. Mine tested good, but I'll swap it out nonetheless.

[Jeffhs]

Ryan, I didn't think you were working on TVs anymore. Didn't you give up your workshop some time last year?

[AUdubon5425]

Well, this one's sitting in my front room (for now) - just have to put it back together after working on it.

[wa2ise]

Originally Posted by fsjonsey

CB'ers are the reason 6LF6's are so rare today. The 6lf6 was commonly used in illegal CB Linear amps back in the 70's, mainly because it was a cheap and readily available sweep tube at the time.
These Linear amps were generally very poorly designed, splattered harmonics everywhere, and ran the tubes way beyond their max plate dissipation ratings. ...

"Dedicated" CB'ers are still using many of these amps, ... However, most of these guys aren't exactly the sharpest knives in the drawer, so I doubt that will happen any time soon.

I know a ham friend who rebuilt one of these illegal linears for a neighbor of his, to reduce the harmonics and make it work better. Mainly so this CBer wouldn't produce interference with TV reception, which the neighbors would blame on my ham friend.

The sharp freeband CBers, now that the sunspots are at a minimum (which makes for a lack of "skip" on 27Mhz) likely have found out that a general or extra class ham license no longer required Morse Code, just a written test (albeit a non-trivial test). And sworn off freebanding in exchange for legal worldwide DX communications.

[AUdubon5425]

I replaced that bad three-section cap and the set came alive. I can't seem to get the brightness and color/tint right unless I just press the Chromatic button, but even then it needs help. Also, the focus changes with the brightness and color controls.

I couldn't pry open the original cap, so I mounted a terminal strip for the new filter caps:


With Chromatic activated:


Without:

[radiotvnut]

You'll probably need a new focus divider. Very common failure in that set.

[freakaftr8]

Yup, but the CRT looks strong! Good job!

[AUdubon5425]

Well, the brightness is almost at max to get a viewable picture - I know this set sat dormant for some amount of time; I'll have to dig out the CRT tester to see if the tube is weak or I have other issues.

The focus control was maxed out too - turning that down helped a lot. I played with the thumbwheel and knobs on the yoke and eliminated most of the shadowing. Adjusting the color and tint does cause the picture to shift - radiotvnut suggested checking the resistors on the focus control board; a quick check showed two reading at twice their value but I didn't have time to take them out of circuit to get a correct reading. The interference is still there - I thought it may be the Atari adapter box but a new balun made no difference.

One thing I thought was funny was that there's a constant static noise coming from the HV anode cap the entire time the set is running.

[zenithfan1]

That noise is probably small arcing from the goo that Doug was talking about. It will make for a bad connection. Discharge the CRT and clean the button and anode wire really well with alcohol then use a small amount of di-electric silicone around the boot to make a seal to the tube. That should stop the noise. Neat set, hope you get er right.

[freakaftr8]

Zenithfan and Doug are right on the spot on that goo, my emperor was arcing pretty good and there was some nasty goo there running down from the anode. Discharged the CRT and used some clorox cleanup wipes on the CRT. Arcing was gone. Those boots on the anode seem to warp outta shape.

[AUdubon5425]

Well, I thought cleaning it thoroughly with Windex would do the trick - I'll get in there with some alcohol tonight and try to find my tube of dielectric grease.

[freakaftr8]

I don't think you want to use dialectric grease.. You should use silicone to breach any voids between the cup and the glass, non conductive RTV is what I used. Works like a charm.