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#1
02-03-2012, 09:20 PM
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Grey blank screen
On my old Panasonic top loading VCR, when you have an RCA cable in the line in on the back, and the device off, on every TV I have used, it would be a black screen, because it was blanking (or it's supposed to be).
On my TV in the sig, I get a half grey screen and a half blanked screen. Why isn't the entire screen blanked? Last edited by lnx64; 02-03-2012 at 09:37 PM. 
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#2
02-03-2012, 10:31 PM
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hey, a timely thread for me, as I cleaned my connections on my '76 color tv which is the " video experiment " tv paired with an old Hitachi Ultravision VHS and JVC VHS camera... Using Belden lo-capacitance RCA cable for the composite in, and B-R brand RF cable... 91%isopropyl alcohol and sandpaper.
I was going to suggest that perhaps you've got a questionable connection in the cabling somewhere. I did. Flashing raster, mostly. Otherwise, it's entirely possible that the tvcr reacts in a novel way instead of blanking the pix... I had a tv which did this. it was a mid-70s Sylvania console I trashpicked. It worked well but with a reduced vertical... got rid of it before I could fix it as it was among the 1st tv's I ever found. Anyway,,, a dvd recorder unit with RF output yielded a brightish, irregular raster. I manipulated the brite and conny to make it appear blanked, yet a strong signal was washed out & overloaded. Possible tuner or I.F. issue.
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#3
02-03-2012, 10:50 PM
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Rather than sending a true black video signal with sync, the VCR's modulator is probably transmitting a dead RF carrier on channel 3 (or 4). Then, it would just be random that the one TV does not display an all-black picture.
__________________
Chris Quote from another forum: "(Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did."
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#4
02-03-2012, 11:15 PM
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My Silvertone roundy goes to gray on no signal conditions as do most of my pre-electronic tuner sets. What you describe is likely perfectly normal for that set.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#5
02-03-2012, 11:20 PM
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One of my ctc16s was doing that and I thought it was normal because it had a watchable picture. Turns out it had an open resistor and the 1st IF tube was not getting power. Now it has snow and a great picture
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#6
02-03-2012, 11:30 PM
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Hmm, this is what it does.. See what I mean, it's a freaky raster.
So it may be normal on these old sets? But then it could be a resistor problem? The TV picture overall, other than the golden yellows, is absolutely normal.
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#7
02-04-2012, 01:50 AM
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um, hello again.. the freaky-raster appears to be a rolling vertical bar, is that correct? Or does it just sit like that? unlikely, i'd think.
it sure is entertaining how you once stated the 'golden yellows' were a thing of magnificence, yet here you cite them as an abnormal occurence 
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#9
02-04-2012, 03:35 PM
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The vert sync circuit is very good, but the vert freq most likely goes way off without a signal.... That is my guess... I have seen this before too.... And I think its also a blank signal from the rf modulator ( no sync) as mentioned above.... Loop a wire from that scope to the picture tube face and see what the vert osc does when you lose a signal.....
__________________
Yes you can call me "Squirrel boy"
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