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  #16  
Old 03-24-2018, 09:38 PM
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The cheapest iron at Wallmart will be fine for most PCB and light chassis work. If you can find a 75-150W cattle prod iron, those are awesome...You can make a chassis ground point wherever you want, normal terminals melt instantly, you can unsolder shield plates that are joined with solder easily, etc, etc...Joy to work with...Till you accidentally melt something plastic (the small ones can do that too).
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  #17  
Old 03-25-2018, 05:51 PM
albanks albanks is offline
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Quote:
Originally Posted by Notimetolooz View Post
One of the first things you should do is clean the chassis.
It's funny you mention that, I did just that! A lot of rust came off, chassis is now looking good.
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  #18  
Old 03-25-2018, 05:55 PM
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I've discovered paper caps are pretty easy and straight forward - when there is enough room to work! Some of these caps have no lead length and are behind several layers of resistors and other parts. I guess the engineers didn't intend for anyone to be recapping 50 years in the future. I also have several books from the 60's and 70's and capacitors are never mentioned. I guess this is a very modern thing we have to do.

Thanks for everyones help. I will have about another 6 questions soon in case anyone else will want to answer and help out. Cannot wait to get done and turn on the TV and see if it works, lol.
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  #19  
Old 03-25-2018, 08:37 PM
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Note: when cleaning the above chassis take care not to leave any rust, dag flakes, solder splash, other conductive stuff on those above chassis terminals... I've seen dag flakes burn up, and I've seen power resistors burn up from a solder blob short (that I made resoldering stuff in the HV cage). Those exposed terminals are great for troubleshooting till conductive crap lands on them...Then things go downhill fast.

By the 60's most 'paper' caps had mylar in them(as part of the paper dielectric layer) or were really full mylar caps. Most 60's and newer sets don't 'need' the paper caps changed since the mylar prevents leakage...Granted the paper/mylar sandwich types tend to drift in capacitance as the paper degrades which can be an issue.

Mid 50's and older sets (late 50's early 60's was the transition to mylar) used full paper dielectric caps and lit from the paper cap era does warn of bad caps...If you do 50's sets and know what stock caps and soldering look like, then you'll find many 50's sets had several paper caps changed when close to new.

Sets ~1964 and newer I don't change anything but the lytics unless I have confirmation/diagnosis of cause of failure.
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  #20  
Old 03-26-2018, 08:46 AM
albanks albanks is offline
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Originally Posted by Electronic M View Post
Note: when cleaning the above chassis take care not to leave any rust, dag flakes, solder splash, other conductive stuff on those above chassis terminals... I've seen dag flakes burn up, and I've seen power resistors burn up from a solder blob short (that I made resoldering stuff in the HV cage). Those exposed terminals are great for troubleshooting till conductive crap lands on them...Then things go downhill fast.

By the 60's most 'paper' caps had mylar in them(as part of the paper dielectric layer) or were really full mylar caps. Most 60's and newer sets don't 'need' the paper caps changed since the mylar prevents leakage...Granted the paper/mylar sandwich types tend to drift in capacitance as the paper degrades which can be an issue.

Mid 50's and older sets (late 50's early 60's was the transition to mylar) used full paper dielectric caps and lit from the paper cap era does warn of bad caps...If you do 50's sets and know what stock caps and soldering look like, then you'll find many 50's sets had several paper caps changed when close to new.

Sets ~1964 and newer I don't change anything but the lytics unless I have confirmation/diagnosis of cause of failure.
oh, wow so what am I recapping then? This set is from the late 60's or early 70's. I assumed it was customary to swap out all the capacitors with any old set. By the way, I should be more clear with my terminology. I think I am using the wrong term. When I say paper caps, I think they aren't really paper, more film drop type. I might open this thing up again soon, I will take some pictures. I am trying to come up with a game plan for the electrolytics currently.
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  #21  
Old 03-28-2018, 01:29 PM
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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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  #22  
Old 03-28-2018, 06:00 PM
albanks albanks is offline
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Quote:
Originally Posted by Notimetolooz View Post
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.
This TV is a 1971 Zenith Chassis 14b38. Definitely a tube set. There are absolutely no viable newly manufactured can capacitors for sale that will work so I have decided to go the 'restuffing' route.
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  #23  
Old 03-28-2018, 06:20 PM
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Quote:
Originally Posted by Notimetolooz View Post
Tube set production ended approximately in 1970, that's about where I
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.
You're a bit off. 1975 was the year that most of the major brands killed their last tube/SS hybrid chassis. The GE Portacolor (lasting as a production tube product till at least 1978) being the major exception (along with some small/foreign made names). If you are arguing from an ALL tube (no tube SS/hybrids) standpoint then you're probably late...Hybrids depending on how you define them date from the beginning of the category of PN junction you classify as SS to at least the late 70's.

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.
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  #24  
Old 03-29-2018, 12:24 PM
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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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  #25  
Old 03-29-2018, 07:16 PM
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So the fact that I am missing this wire, and there is nothing subbed in as Zeno suggested, should I just run some wire and connect to the new can I will be rebuilding? Picture shows from the Sam's how it should be, running from the area where the horizontal hold control is to 1 of the terminals for the larger electrolytic. My situation is that there is currently no connection, no wire, nothing, just empty terminal. What is the consequence of this, just no horizontal hold function? I'm not sure why it would be set up like this.
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  #26  
Old 03-29-2018, 08:57 PM
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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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  #27  
Old 04-01-2018, 08:48 AM
albanks albanks is offline
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Quote:
Originally Posted by Electronic M View Post
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.
OK thanks for the advice. When I open up the back again soon after rebuilding the cans I will take a look.
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  #28  
Old 04-01-2018, 09:57 AM
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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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  #29  
Old 04-02-2018, 06:20 PM
albanks albanks is offline
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Quote:
Originally Posted by zeno View Post
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 !
I will check this out when I open it back up. I bought a replacement NOS can before I decided against chancing it with dried electrolytes. So when I rebuild the can and open the set back up to install it I will check what you said, take some pictures to post here as well because I will want to rectify any potential mistakes and that seems like a potential problem.
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  #30  
Old 04-03-2018, 08:24 AM
albanks albanks is offline
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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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