Hi.

I'm a new member here. I've been lurking here for quite a while, and finally decided to join :) I really enjoy hearing about and looking at others TVs.

My favorite TVs are from the late 50's through the early 80's. I also enjoy color roundies (although I don't own any.) I have 12 TVs right now, and most are from the 70's. I'll post some pics later.

I won the B&W Zenith TV with the digital tuner that was in this

thread (http://www.audiokarma.org/forums//showthread.php?s=&threadid=18317) It gets really good sound for being just a portable set. The thing I didn't expect was it has full DC restoration.

It does have a shrunken picture with vertical foldover at the bottom. It is most likely an electrolytic cap problem. Does anyone have the schematic for this set? I just want to identify the caps in the vertical section.

Thanks

tv beta guy,

Someone could have been twiddling the v-height/linearity controls in back of the set. I've seen this cause vertical foldover as well as a reduction in vertical height of the picture. I would check those adjustments before digging into the circuitry. If you must go into the set, be sure you have the schematic.

The picture looks good even with the raster distortion, but that's Zenith for you (or was, before Gold Star got into the act). Most Zenith TVs from the beginning until the '90s were excellent sets. The original Zenith Radio Corp. of Chicago really knew how to build good TVs. I've had several in my life (still have a nearly-ten-year old Zenith 19" color set that works absolutely great on cable), including a non-digital version of your 12" portable (bought in 1978, it lasted over 20 years and was still working when I finally got rid of it four years ago). I've liked them all. Very few repairs required on any of my Zeniths (none, yet anyhow, on my Zenith color set :thmbsp: ), but again, that was a hallmark of the company in its pre-GS era. Too bad "the quality went out" when the company was sold and went offshore. :(

There is a vertical height control, but it is not located on the rear of the TV. Linearity is good. Tried to adjust the height, and after it gets to where you see the bottom of the picture now, the top continues to increase normally and the bottom starts folding over.

It is a shame what has happened with the quality of Zenith after Goldstar took over. My uncle has a 27" Zenith from 1997, has already been repaired once, picture looks terrible. Dim, not very sharp, color bleeding, on screen display that sometimes doesn't work correctly. My grandparents have a 25" console Zenith from 1993. It is a Goldstar, still works, but has been repaired numerous times, picture looks terrible also, even after I redid the grayscale and touched up the focus and all.

What I have done with some success is to trace the vertical yoke leads back to the circuitboard...the vertical output capacitors are likely in this area. If you don't have an ESR meter to check capacitors in-circuit, it may just be necessary to do a shotgun approach of replacing all the electrolytics that appear to be connected to the vertical circuitry.

Hello tv beta guy,
If you know where the vertical output transistors are in the set look at the reference number for them stamped on the PC board. Example- Q61=vertical output transistor 1. All the other components relating to the vertical output section would start with a 6. So, electrolytic caps in the vert output section would be numbered C65 for example. Also, another way to check electrolytics in circuit if you don't have an ESR meter is to use a multimeter with capacitance function. It won't be as reliable as an ESR meter but it will give you a pretty good idea if an electrolytic has dried out. If the cap says 100uF on it and it measures say 5 or 10uF in circuit then chances are very good it is opened up or nearly so. Good luck with your set.

Jeff

Thanks everyone for your responses.

I don't have an ESR meter, so I'll just try a new cap in the vertical section one by one till it's fixed. I have to order some more caps, ran out of certain values in my stock. I will post an update once it's fixed.

I uploaded a few pictures of my other TVs in the photo gallery.