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#1
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The earlier-late '40s ones were, I think...
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Benevolent Despot |
#2
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This question has nothing to do with radio, but how to you guys get these big, nice photos to upload? The window I use to post pics here restricts to a very low pixel count, which looks like a postage stamp when placed. I have nice pictures to show!
....back to the K731 talk. Brad, your Zenith looks swell! Love the dark, almost cherry finish and that cabinet is the style I favor. The antenna leads should be soldered, and I'd check the paper caps underneath for leakage. The big, series dude on top should be checked too, but those seem to last a lot longer. You'll have to pull the chassis to see them and don't forget to keep it unplugged; these are fully hot when connected. Last edited by Nolan Woodbury; 03-31-2006 at 07:25 PM. |
#3
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Nolan - I use PhotoBucket.com to store my pics. Thanks for the tips but I right now I have much simpler problems.
Where does the green wire off of the antenna go? I can almost make it out in one of my pics but I am not quite sure. Brad |
#4
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The 12DT8 is the only tube used for FM, and not AM. So try it first.
The dot before 100 is for Zenith's own FM station in Chicago. A handy dial calibration point at the factory? See if there's a wire broken off at the tuning cap - could be where the green wire goes, since the white wire doesn't... |
#5
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If you need a schematic of the K731
Go here:
http://techpreservation.dyndns.org/s...ics/Zenith.htm And choose 7m07 as the model number. (I'm fairly sure this is the model #) |
Audiokarma |
#6
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Tube function:
12DT8 FM RF amp and convertor 12BE6 AM convertor 12BA6 1st IF 12BA6 2nd IF 12AU6 FM limiter (3rd IF) 14GT8 or 19T8 FM discriminator, AM detector, 1st audio amp 35C5 audio output |
#7
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Nice radio. Mine is the 7K07 chassis and I'm still trying to find a schematic that actually matches the radio. I've looked at the 7M07 and the tubes are slightly different, but the rest might be the same? Any suggestions?
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#8
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Quote:
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Jeff, WB8NHV Collecting, restoring and enjoying vintage Zenith radios since 2002 Zenith. Gone, but not forgotten. |
#9
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Off hand, I don't know where the green one attaches Brad, but I have a K731 handy to peek inside if needed. PM me or respond if you need me to track this down-
Thanks for the kink...I now realize if you pull photos from a URL, there's no size restriction... |
#10
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7K07 chassis is coverd in Sams folder 653-12
7M07 is in 778-10 Check with your library, or the online sources I have mentioned elsewhere. |
Audiokarma |
#11
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Quote:
What is Sams folder? I was able to get a Djvu schematic "Model T350 R & W Chassis 7M07". I hope this is the correct one? Thanks, Brad |
#12
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That green wire from the antenna should connect to the part of the tuning cap that is also connected to pin 7 of the 12BE6. You may have it connected to the oscillator coil section by mistake.
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#13
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AM Green Wire?
Nolan-
I can't figure out where the green AM antenna wire goes. I do have a schematic of the chassis but with my limited knowledge of electronics, it doesn't help much. This is where I attached it, but it doesn't seem to fix the problem. The AM worked well until this wire fell off. The wire is attached to the tuning capacitor now, but this must be wrong since I still have can't receive the AM band. I took 12BE6 out to get a better photo. Once I get this running again, I'm going to give it a good dusting! Thanks for your help. Brad |
#14
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The antenna wire should connect to the capacitor section with larger plates.
Sams published (and still does!) the "Photofacts" folders - most service shops subscribed. Each one is 4-16 pages - schematic, parts list, photos. You can buy them from Sams ($25 or so...), but there are a lot of copies out there - I have over 1000 myself, most gotten for free. Online sources: michelletroutman.com infotronix.us findatube.com Last edited by Tom Bavis; 04-02-2006 at 11:21 AM. |
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Here's your location
All of the posts regarding the location are correct, but these pictures should clear it up nicely.
http://i78.photobucket.com/albums/j100/nolanwoodbury/K731C.jpg Note that the wire connects to the tuning cap, then runs a separate wire that loops through a hole in the bottom of the chassis that connects to (I believe) pin 7 of the 12BE6. Not sure of this, 'cause the markings are worn and this radio has no tube identifier-label on the bottom. Still, it's the tube closest to the tuning mechanism. http://i78.photobucket.com/albums/j100/nolanwoodbury/K731E.jpg |
Audiokarma |
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