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#1
11-21-2009, 01:50 PM
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63 Zenith Roundie
I purchased another Zenith roundie 25mc33, it has a strong CRT but has tuner problems it will recieve UHF fine but no VHF input from DVD/vcr/Direct tv
has a snowy picture, the picture fluctuates but no images/ program sound. Where do I start on this? Last edited by Kalamazoo-DJ; 11-21-2009 at 02:38 PM. 
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#2
11-21-2009, 07:14 PM
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Zenith Tuner Failures
Try replacing the 6HA5 first in the tuner then the 6GJ7. See if that works. I used to see failures of the 6HA5's that would cause this problem.
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julian Last edited by julianburke; 11-22-2009 at 02:14 PM.
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#3
11-21-2009, 10:48 PM
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Ok thanks I have a twin to it so I will switch tubes
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#5
11-22-2009, 09:41 AM
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The 6GJ7 is the mixer oscillator in the tuner. Whenever I find an old zenith, most of the time both 6HA5 and 6GJ7 are toast. That TV is actually a 1965 model.
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I tolerate the present by living in the past... To see drh4683's photo page, click here To see drh4683's youtube page, click here
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#6
11-22-2009, 01:37 PM
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Quote:
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#7
11-22-2009, 01:57 PM
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There are instances in which the 6GJ7 may check fine, but its characteristics changed enough to the point where it won't oscillate on any frequency, or sometimes it will only oscillate on the high or low end of the VHF section. Try subbing the tube out. How is that tuner? Dirty contacts? Also, very very common for the fine tuning gear that turns the slug on the VHF tuner strip develops a crack split down the middle, where it just spins on the shaft. 9 times out of 10 they are cracked making fine tuning impossible. I take it apart, and drop a touch of super glue on the shaft and spin the gear around really quick to distribute the glue before it sets up. It works perfect and the trouble won't come back.
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I tolerate the present by living in the past... To see drh4683's photo page, click here To see drh4683's youtube page, click here Last edited by drh4683; 11-22-2009 at 02:02 PM.
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#8
11-22-2009, 02:06 PM
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Quote:
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#9
11-22-2009, 09:58 AM
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OK thanks for that year clarification I was only going by a repair tag I found under the cover probably from another nearby Zenith
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#11
11-23-2009, 05:27 PM
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I will get it fixed, I am working on a 3rd Zenith and an RCA purchase also you might be intersted in that one
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#12
11-23-2009, 07:06 PM
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tuner problem
Something doesnt look uniform inside the tuner connections, it appears solder is broken and the white wire near the brown antenna lead, how should this really look? there is one soldered and one hanging loose.
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#13
11-23-2009, 08:39 PM
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Those are great sets. I have had mine for two years now and I love it. I took the tuner apart on mine to clean the contacts. It is not that complicated, just be careful where everything goes.
I noticed you are missing the arched wooden piece that is supposed to go between the two front legs.
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Just look at those channels whiz on by. - Fred Sanford
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#14
11-23-2009, 08:57 PM
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I like these sets alot also, this one never came with the arched leg peice there is no place eveident it was removed/missing.
This winding is causing my tuner issue, if I knew points where it was originally soldered, I could easily resolder it back on, any tips or know hows? this is at the IF connection
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#15
11-24-2009, 06:51 AM
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Quote:
You might need a schematic to determine where that coil is soldered.
__________________
Just look at those channels whiz on by. - Fred Sanford
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