Sven has a new home, but he's not feeling well

[veg-o-matic]

Whew.
Got me a cool Zenith B/W console, courtesy captainmoody (thanks, cap'n!) He arrived yesterday, MI to MD and only had one small bash--pretty good, considering the condition some other things have been in! Sure was fun getting it from the loading dock at work to my car, then from the car into my condo. Thank goodness we have an elevator!
Here's a recycled pic. Can't post a new one until I get my den shoveled out...



Since his style seems to be Danish Modern, I'm calling him Sven.

Anyhoo... I pulled the back off expecting the worst and discovered that only one tube had worked loose so I punched it back in. Connected a VCR to the antenna terminals and fired him up.

Well.

Got me a raster, though it's not quite as wide as the toob itself; no sound. Poked around a little bit and noticed that all tubes lit up except three--the IF stages (do I sound like I know what I'm talking about? I got that info off the where-the-tubes-are-sticker-thingie inside the cabinet!) I reseated all three tubes and got stages 2 and three to light but #1 was still dark. Could this be why I'm not getting a picture or sound? The tube is a 6BZ6 if that means anything to anyone. The set itself is model #M2737U with chassis #14M23.
If replacing that tube would magically make the set work, it'd be totally cool. I realize life doesn't work like that, though. And what about the horizontal width? Any way I can adjust that withough killing myself or putting out an eye?

Does the VHF channel knob pull off? The channel numbers looked good at first but then some of them looked like they got covered up. Seems like there might be a piece of tape or something in there that needs to come out. I pulled it gently a little, but was afraid to really yank in case I busted something beyond repair.
I'll get it one of these days!

[Chad Hauris]

If one of the IF stages is not working, the entire signal path for the picture and sound is broken. Replacing that tube should cure that problem. Try the suspected bad tube in one of the other known working 6BZ6 sockets just to make sure the filament really is bad.

Some Zenith sets use a metal sleeve between the deflection yoke and the CRT for width control. The sleeve absorbs the magnetic energy, decreasing width. Some zeniths have a potentiometer on the back of the chassis for width.
If these don't do it you may need a new horizontal output tube and damper tube.

[kc8adu]

sometimes corrosion forms on miniature tube pins and causes the heater problem you have.
i scrape them with an xacto knife till they are shiny.
just did it to all the tubes in an old utica 650 6m am tranciever.got rid of all the intermittant crackles and pops it had.

[veg-o-matic]

Okay. I replaced the first IF tube with one I pulled out of another TV and got this:

So progress was made!
Then I went ahead and replaced the second and third IF tubes, along with the Horizontal Output tube and the damper. Here's the "after" picture:

I think there's a slight improvement in the picture quality, but as you can see, the width and height are still way off.
Any ideas? I don't see any pots marked
horizontal width or anything similar. There's this weird little wire coming off the yoke that looks kind of like a little handle. It's a stiff wire, I mean, not one that carries power. I hope! Would this have anything to do with the width problem? If I'm supposed to adjust it, do I do it with the power off or on? I'd like to get Sven working without giving myself a perm!
As always, your help is most appreciated.

[Eric H]

Someone has mentioned that the Zeniths use a "Width Sleeve"
This is a sleeve mounted around the neck of the CRT under the yoke. You losen the yoke and slide the sleeve in or out (I think)

You might also have a power supply problem, low B+ from a bad filter cap or rectifier.
Does this set use a 5U4 tube?

[Eric H]

Can you post a picture of the chassis?

[Chad Hauris]

This looks like it may be low power supply voltage to me, especially because the vert. height is low in one of the pictures.
You need to measure the B+ voltage against what is in a schematic to confirm or deny that. Also, the boost voltage could be low---the horizontal output starts out on plain B+, but when the set is up and running, it runs on boost (600 volts or so). Maybe there are some bad caps in the damper section, causing the boost to be low. Many times the boost voltage also operates the vertical oscillator/output. This should also be measured (not at the plate of the horiz. output, though). The photofacts folder/schematic appears to be necessary here to check these possible voltage problems.

[Chad Hauris]

Also, keep in mind that these voltages are very dangerous, there is a lot of current behind them. Make sure you are familiar with all of the safety precautions before attempting to measure the voltages.

[kc8adu]

i noticed the raster is mishapen upper left.
does that distortion move?
if so filter caps.
low b+ is likely.
run it 5 minutes or so and see if the big filter caps are getting hot.

[veg-o-matic]

Hi yall:
I got B+? Well live and learn. As for bad caps in the damper section, well, the whole set seems pretty dry to me!
Gratuitous banana:
Guess I should 'fess up and admit that I'm much more comfortable on the front side of the set than I am poking around the innards. It's only a matter of time until I touch something I shouldn't and wind up dead with bad hair.
If replacing tubes ain't gonna work then I think I'm going to have to haul Sven off to A Professional.
But I thank you for your help. If anyone comes up with any more simple ideas, I'd sure appreciate it.
In the meantime, is it going to kill anything if I continue running Sven in his current situation? Nothing seems overly hot inside when he's on, if that matters.
Bob

[veg-o-matic]

Eric:
Here's a pic of the chassis. I'd point out the tubes I replaced and the little handley think coming off the yoke (I think), but I find myself unable to add arrows to the pic.

Bob The Butterfingered

[Eric H]

The T "handles" are for width or pincushion, I can't remember which. (anyone, anyone?)

You would bend them closer to or away from the bell of the CRT depending what you need to do.

The small circular rings with the tabs on the back side of the yoke by the clamp are for centering the picture, tho they can affect the width somewhat too.

[andy]

...

[veg-o-matic]

Hoo hah!

Ya know, it's amazing what one can accomplish when one
A) doesn't know any better
B) is stubborn and
C) is foolhardy enough to just keep asking "I wonder what this does?"

Anyhoo, possessing all three of the above qualities, I finally found the elusive 'width adjustment sleeve' and got Sven looking mighty fine! I think I would have found it sooner had I realized that it's really no more than a thickish piece of foil. I was looking for something more substantial.

I will post a picture in the gallery just as soon as I suck it off my camera. This isn't a fancy-schmancy collectible set, and there really wasn't anything majorly wrong with it, but it's mine and I'm proud of my first little foray into fixing a TV, no matter how minor it was.

As for the above, I think I'll add D) has friends who know what they're doing and are willing to share!

Many thanks to all of you for all your help.

(A very grateful) Bob

And heeeeeeeeeere's the finished product (sorry the picture's crappy. It looks REALLY good in person!)

[drh4683]

Hey,

That was my curbside find I gave to dwight last april! Glad that someone has it to appriciate it (I gave it to dwight as he would find someone to take good care of it!) man, if you moved that tv another 1/16" that cheater cord looks like it will rip in half!!!
I remember when I brought it home the night I found it, it worked perfect. Since you seemed to have cured your IF tube problem, a thing that I do that always works is to shoot some tuner/contact cleaner in the tube sockets then work the tubes in and out before it evopaorates. That always does the trick. Enjoy!
Doug