#1
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1966 Zenith roundie: Color is back to life!
I got extremely lucky a couple days ago. Back in September I had problems with my '66 zenith diagonal dial roundie. Had some color problems since day I got it, anything yellow looked like lime green. Figured it was some kind of demodulator trouble and went though the alignment procedures via zenith 24MC32 chassis service manual. Everything was going well until it came to alignment of the demodulator quadrature coil (zenith #95-2263). The slug locked up in the core as I was trying to peak out the vtvm. It was a bit loose to begin with, so it cross threaded itself and jammed. Got the slug out, had to break it into pieces so it could be removed without damaging the rest of the coil. Put in a new slug and it just wouldn't take. The formed threads were already damaged and now the slug just slid around inside the core.
This past sunday I decided that I should pull the TV out of the pile and really check things over as its been some time since that event. I pulled the chassis and was going to remove the coil so I could take it apart and see if I could figure out a method of securing the slug yet make it adjustable. Before I did that, I went ahead and double checked my chassis that I had up in the attic. Ive got 15 zenith parts chassis and I've got them inventoried. I didn't actually "check" to see what I had back when I was looking for this coil. I go up in the attic and look at the first chassis. THERE IT IS, a 95-2263. I couldn't believe it! Mounted on what I once *though* was a 24NC31 (which didn't use this coil I needed). Turns out, the chassis I had was really a 25NC37, which is actually the only chassis other than the 24MC32 (roundie chassis) that uses the 95-2263! So the problem was, back in september, I checked my list of parts chassis then looked up the quad coil part numbers for each chassis, none of them matched, so I assumed I had nothing. I never knew that chassis I had was a 25NC37 until I looked at tube layout diagrams in my service manuals until I found a match. that chassis had a missing chassis ID tag, but for some reason all the years I had it I though it was a 24NC31. So there you have it! Make sure you know what you have before you write it down! I had the part I needed all along and only checked just for the heck of it hoping that just maybe one of those "parts" chassis had what I was looking for! As of today, its all back together with the "new" coil, demod circuits completely aligned and working just the way it should be! The picture of the coils you see are the 95-2263. The one with the can pulled off the the original, the one on its side is the one that was pulled from the parts chassis. |
#2
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Great job. Beautiful cabinet. Zenith never got the credit they should have got for their wood work. All solids and venners. No "photofinish masonite". I sold Zeniths from 63 to 70 and realy fell in love with them. I still have a cabinet from a 9630H home entertainment center, The Sorrento.
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#3
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Last edited by andy; 12-07-2021 at 02:14 PM. |
#4
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I have a 20Y chassis for parts if anyone is interested.
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#5
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still looking
I,m still looking for a fly for a 29jc20 chassis, if anyone runs accross one
I wish someone had a zenith cross-reference chart, I,m sure just like Doug said some of these parts are the same, but when they change chassis numbers they like to change part numbers also.
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Audiokarma |
#6
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Andy, The coil is still repairable. The core is not crumbled on this one. It can be saved. Perhaps a small piece of string or extremely thin rubber band down the core would be good enough to support the slugs. The top slug is OK, bottom slug is the one you can't adjust.
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