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It is usually customary to state more specifically what you are working on (model) and generally make each thread about that item.
Some of us here online are a bit rusty reading minds. The first analog commercially successful TVs come out about 1939. In the US analog TV broadcasts stopped in 2009, so that's about 70 years that analog TVs were produced. What "vintage" is depends on ones definition, a lot of times on Craig's list anything before 2009 is vintage! Tube set production ended approximately in 1970, that's about where I would draw the line. However some would put it earlier. Tubular caps progressed through the years from paper dielectric (many times soaked with oil) in a cardboard tube sealed with wax to paper dielectric in a molded plastic case, to paper plus plastic film in a plastic molded or epoxy dipped case, to film alone in a dipped epoxy case, etc. Problems arise because the paper will degrade, molded plastic cases crack and expose the insides to the environment. Probably other things happened also. Some capacitors in the mid 60's may have still used paper. So if your TV was made in the late 60s some of the tubulars are OK, it depends on the construction. Electrolytics before 1980 I would replace. |
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I have some ~1964 Zenith sets still going fine on their original tubular caps...Shotgun recapping tends to be frivolous in sets past 1965...At that point, it is better to troubleshoot the problem.
__________________
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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I was speaking in general approximate dates for the most part. I didn't want to get bogged down in exceptions and what different manufactures did at different times. I know one of the earliest solid state TVs came out in 1959, Philco Safari, but that's an exception.
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Audiokarma |
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Often times back in the day a tech would replace one section of a can (when just that section died) by disconnecting the wire to that section's positive terminal, deleting the wire and adding a new cap on the far end of the deleted wire. Look at the hold control (and any points connected directly to it by wire) odds are a newer replacement cap was connected elsewhere by a repair tech.
If the blank terminal appears to never had solder added to it then maybe it was not connected due to a production change or factory wiring error (yes I've seen Zeniths with factory wiring errors). But if a wire was soldered on and removed then my first paragraph is the likely scenario. Without the schematic, it is hard to definitely say what lack of that cap would do. A lytic is normally for filtering not RC frequency setting. Odds are without it there would be more noise in the circuits it is on...Sometimes that leads to major issues sometimes only minor ones...Zenith sets have a reputation among repair techs of being able to do a damn good job of feigning normal operation despite some major component failure that normally would take out other brands.
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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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See if the old cap is original. If it is or its an OEM replacement
it will have 22-#### on it. Also a 4 number date code & 3 number EIA code sometimes run together. See if the 22-#### matches Sams. There may be a production change also BUT I did a lot of cans on these, enuf to stock them & dont remember one. 73 Zeno LFOD ! |
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Incidentally where do you guys pick up your hook up wire? Seems like a dumb thing to ask but I am looking around for some 20 awg, solid, 600v, high heat, and with good insulation. Maybe it's hard for me to find because I don't need 100ft or more I'm looking for something inexpensive. I need it to rebuild the cans and so even a 25ft spool is overkill.
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Audiokarma |
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Looking good!
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Thanks so much!
I have about 5 consoles waiting to get started on. Would the electrolytic replacement procedure be the same on those or should I get more practice with table tops before moving on to the consoles? I've got two 13" Zeniths I can do next as well. |
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No lets start a food fight
On most sets from the mid 60's on I would not recap. Best thing to do is do only what you need to do to get a raster & evaluate the CRT. After that there are certain caps that should go. Can caps are often bad. Most will run hot or be leaking mung out the bottom if bad. When you get to early solid state sets cans almost never failed. Example is Zenith CC2 sets. I probably fixed an easy 1000+ of them and only changed 2 or 3 cans all causing white hum bars due to bad filtering on the 24 V supply. Best bet is as you start on your pile post the brand, model & chassis numbers along with a nudie of the chassis. That way you can be forewarned of any special care needed when you restart it for the 1st time. Changing cans in consoles is no different. With Zenith sets from abt 1975 on the chassii were almost the same from 13" - 25". If your 13" sets are solid states they have a console chassis stuffed into a small box but still serviceable ! Enuf fer now 73 Zeno LFOD ! |
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Thanks for this valuable info. I am going to enjoy the fruits of my labor on this set and then take stock of where I stand for the next projects. |
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Forget the 13 inchers. Opened it up - zero room to work. These things were meant to be thrown away long before any electrolytics would have dried out and need to be replaced. Will move on to consoles.
Quick question: I have a mid 60's Zenith rectangular b/w console with incredibly strong CRT. Did what Zeno said, turned on just to get an idea before I start. Picture is twisted. I guess this is a yoke thing. Does anyone have a link to the procedure for getting the picture to display straight? |
Audiokarma |
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