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Old 10-16-2008, 12:26 AM
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drh4683 drh4683 is offline
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Join Date: Jan 2003
Location: Chicago, IL
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Thanks for the kind words everyone.
This evening (or should I say yesterday), I powered up the big 25" zenith for the first time. I pulled the HOT, and powered it up with the variac. The set was unplugged and appeared to have been untouched in years. From how the house was layed out, I believe this TV was the "basement" TV since day one. There was similar vintage furniture arrayed around the TV, and across from the seating area was the usual built in bar that everyone had. I don't think I've ever set foot in a 1950's/1960's home that didnt have a built in bar in the basement with wood paneling all around. Maybe thats a midwest thing, I don't know if its like that everywhere else in the US.

Back to the topic, after a slow power up, I had good sound. I plugged the 6LB6 back in and powered it up again. Had a picture with snow! Hooked up the antenna and as usual, a near perfect picture. I could'nt believe how crisp the picture was, and bright too. Its another lucky TV that survived, never had the back pulled off in 40 years until I came and saved it from its death at the end of the estate sale.

Its not 100% working perfect, the vertical is a bit short, not a tube either. So it will require some troubleshooting. A good chassis dedusting is also in order. My usual routine is to test ALL tubes in a recently aquired TV. Of the all original tubes, 3 were bad. Shorted 6U10 (rare), weak 6Z10 (the ususal), and a shorted 6GH8 (as expected).

I'll get into it tomorrow. Today was just the test out day to see what it was kind of shape its in. Its certianly a low hour set, for which I am pleased. The HV was running high at 28 KV when I first powered it up. Zenith with that ridculous "hollow shaft" HV pot makes it tricky to adjust the HV without the adjusting tool, which I never was able to find. A tapered flat head screwdriver always works though. The regulator is in good shape, brought it down to 25KV still within its adjustable range. The usual component drift. However, Im a bit concerned with the sweep transformer. That thing runs hotter than hell. I have an NOS one for this chassis should it be required. I've yet to check the cathode current. This is the same flyback used in the 20Y1C48/50 and 16Z7C50 chassis, and Ive had a couple of those crap out on me over the years.

Ha, as I sit here typing this, I'm monitoring the set. Now its intermittently flashing into a blank raster with the side pulled in. I know right off the bat thats an intermittent open vertical blanking transistor. Thats because one of my 16Z7C50 chassis sets had the same problem about 4 years ago. I went in circles trying to find it, little did I expect the vertical blanker to cause such a problem. Sure enough, replacment cured it for good. The original one had intermittent low gain which caused the problems. Im sure there will be more to come. A TV can't be flawless after almost 40 years of existance!

So that's where it stands for now. A few little things to work out, but thats where the fun is, in the repairs and getting it back up to par. Photos to come shortly....
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