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Starting a Zenith 16h23
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I picked up this very beat up Zenith 16h23 chassis set years ago. I didn't know much about TVs back then not that I'm an expert now, but I figured for 25 bucks I'd give it a shot. The photo finish cabinet has no photo finish left on it and some water damage. But after replacing half the tubes in it the set actually works pretty well it doesn't even Buzz. Here's the first half decent picture I've gotten on it. This is all original capacitors and resistors. It has a lot of Separation in the top of the vertical , and doesn't have full deflection to the bottom , also the horizontal hold never really locks in right , you end up with like a wave in the screen . I'm going to run through this one section by section again but I'll put up more pictures. Then I think I'm going to vinyl wrap the cabinet in wood grain, and use some toner on the plain wood on the front.
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Two very common problems those chassis had were a bad capacitor in the vertical section, a .022 connected to pin 5 of the 6EM7, and a bad resistor in the horizontal circuit, a 100K connected to pin 1 of the 6GH8.
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I took the four bolts out for the chassis, and I couldn't get it to budge. The Sam's Instructions make it sound like the picture tube is connected to the chassis but I don't see anywhere that it's connected. In The Sams it tells you to remove the tuner speaker and switch those all make sense, then to remove the plastic mask on the front of the cabinet and Slide the chassis out the front with the picture tube attached. Is this right?
Also I have to say the service saver chassis is all marketing. I looked underneath there's like to 4-in holes under there how could you work on anything |
There should be quarter inch screws with washers around the outside perimeter of the CRT attaching it to the bezel, one or two on the top and also on the left and right. Be careful pulling the chassis and CRT out as the CRT is supported with that bracket around the yoke and you don't want to exert too much pressure as it's removed from the cabinet.
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Your set isn't a proper service saver cabinet. The proper ones have a chassis cutout in the bottom board no more than 3" smaller than the outer perimeter of the chassis and a sheet metal cover with vent slots. Perhaps yours was made during the transition to service saver and has an older cabinet with a newer back.
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I'm going to be posting pictures later today, but I'm having trouble with the horizontal lock. It's extremely touchy and unstable. Replacing the cap you've spoke of and the resistor did help but still having some issues. |
Hey guys it turned out the diode was bad for the horizontal lock. I was able to find a New Old Stock one from Talon Electronics. After that my horizontal was much more stable. I went through and recapped the horizontal section, I found that the damper tube was microphonic, and the capacitor that goes across it was bad also. At this point there is no more wax paper or Black Beauty capacitors left in this set. There is a few of the zenith Brown rubber looking capacitors left.
The biggest problem I'm having right now is that when I adjust the contrast or brightness this picture shrinks horizontally. I've replaced the 1b3, I replaced capacitor C3 which was shorted, and the damper tube along with the 6DQ6. I'm not really sure what to go after next. What is interesting is if I set the brightness and contrast lower and the picture shrinks if I leave the TV off for 10 minutes or so and turn it on the picture actually fills the screen and starts to shrink . Also the bottom third of the picture is crystal clear and actually looks pretty decent from there up I'm getting Rippling lines through the picture. I thought this was 60 Cycle hum so I replaced the filter caps but this made no difference. I've heard zeniths can be difficult. I think this thing has been through the ringer. Almost every tube tested week in the set. I think I have three original tubes left. |
It's hard to get it to show in the picture but you can kind of see the lines
https://drive.google.com/file/d/1q3o...w?usp=drivesdk https://drive.google.com/file/d/1Fso...w?usp=drivesdk |
Another problem with these was the vertical integrator. It looks like a brown ceramic capacitor but has three leads coming out. There is a three digit number on them which you can put into your search engine and find out the insides, If I remember correctly is three capacitors and two resistors. That's if I remember. These cause vertical symptoms like the picture you posted.
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I thought if the vertical integrator was bad, you wouldn't have any vertical lock? |
The only thing I can see wrong with that picture is the vertical linearity is out of adjustment. Stretched at the top.
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My 25nc33 had a bad integrator that caused linearity problems. I'll check the schematic tomorrow but I think it may have two integrators.
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There's usually 2 vertical stage "K" networks (aka RC couplates) one is used as the vertical integrator for the sync, and one is used as feedback from the very out plate to the first stage of the vertical multi vibrator....If it goes bad it can kill the vertical, cause linearity issues or the vertical can stop and start with weird linearity issues throughout....I had a roundy where a previous tech put in too low of voltage rated micas in their replacement for vertical feedback and it was a PITA to troubleshoot.
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Thank you there are 2 K networks in my vertical. I'm guessing it would be the second one closest to the vertical transformer that would be the issue?
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Just a thought I'm pretty sure I ordered Discs incase I had to build these. Should they be micah? |
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