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#1
04-22-2015, 08:40 PM
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Horizontal Sweep Adjustment?
The horizontal went out of sync on my 1960 Emerson console,
I got a new Hor.Output tube, and now after the set warms up, it straightens out, but takes about ten minutes... There is a Horizontal sweep adjustment on my schematic, which I never attempted before: it says to connect a clip lead across the Horizontal Stabilizer Coil... What does that mean? Do I use a wire with two alligator clips? Across what parts of the coil? Thanks for any help! 
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#2
04-22-2015, 10:11 PM
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Quote:
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#3
04-23-2015, 10:42 AM
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Why did you replace the output tube for a synch problem? The output tube should be replaced for lack of deflection width. And the OSCILLATOR tube (and horizontal AFC tube or SS diode pack) should substituted or replaced for horizontal synch problems.
__________________
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
04-23-2015, 09:48 PM
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Sorry, I probably didn't use the correct terms...
What happens is when I turn the set on, the screen has lots of lines, just like if the horizontal hold needs adjusting... after about 15 minutes, they get fewer and fewer then the picture pops in clear... I replaced the Horizontal tube only because I tested it, and it failed the life test on my tube tester, so I thought that could be the culprit. The Horizontal Hold adj. doesn't work till the set warms up for those 15 minutes... Even still, after the picture pops in, the picture is shaky and the images bend to the left and right...
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#6
04-23-2015, 10:35 PM
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Probably a slight adjustment of the Horiz stabilizer coil would center the horizontal hold, however you say it's shaky in any case so possibly the horizontal AFC diode is bad, at least I would guess a set of that vintage uses a solid state diode, actually two diodes in one package in most cases.
They are usually a small rectangular plastic component with three legs. Like these. http://www.ebay.com/itm/Qty-2-ECG-11...item1e9d2e8169
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#7
07-09-2015, 06:09 PM
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Are these AFC diodes possible to find? Do I have to find NOS? The schematic says I can use a: R-2749 or a 2N408. I included a photo of the diode in the Emerson chassis right now... Anyone know where I can get one?
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#8
07-09-2015, 06:59 PM
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You may be able to use a DVM in "diode" mode to test the diodes. One way should read around 0.3V, the other way an open circuit.
You could probably use a pair of 1N914 or such small signal diodes as replacements. Nothing special about the pair inside one package.
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#9
07-09-2015, 08:03 PM
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#10
07-09-2015, 09:25 PM
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Just realized I don't have a "diode mode" on my meter...
So, I guess I should just replace it anyway. If I get a pair of 1N914 diodes, how do I put them together? There are 3 leads coming off the original diode... Or should I just look at the schematic and try to figure it out?
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#11
07-10-2015, 12:07 AM
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In all probability it's common-cathode*. Check the schematic to be sure. The banded (cathode) ends of the replacement diodes would go to the middle leg.
- *Rarely seen are common-anode and series type.
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#12
07-10-2015, 11:43 AM
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I installed these, just got them from Radioshk today. No improvement, seems a little worse if anything. I wonder If I bought the right diodes? They say: 1N914 1N4148
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#13
07-10-2015, 02:16 PM
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A few notes
First either your set is a 1964 or 5 or the diodes have been changed before they have a date code of 1964 38th week. Keep in mind for the future these come 3 ways. Common anode, common cathode, & series. Common cathode is almost always what is used. If that dont do it a tube is next. If not a tube probably a cap is drifting, watch out for the clear silver jobs. The tube should be cheap compaired to a hoz out. 73 Zeno 
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#14
07-10-2015, 06:38 PM
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How's the vertical lock, nice and strong like it should be? Or drifty like the horizontal?
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#15
07-12-2015, 03:08 PM
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Oh, be aware that it won't work right if you have the replacement diodes, one or both, in backwards. Carefully remove them from the circuit board (so traces don't peel up) and tack solder the old diode package back in.
You want to avoid creeping layers of errors and defects from making life harder.
__________________
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