1950s or '60s vintage Zenith TVs, Need some info

[vortalexfan]

Originally Posted by dtvmcdonald

NO NO NO!!!!!!!!

It does not have the words "sensor safe" ... this means that it contains acetic
which exudes out on curing and will corrode the wires. If it smells like vinegar or
other acid, don't use it!

Ok, well I'll return it then. Where would I get the "sensor safe" stuff then? Would they have it at the Auto Parts store? I'm asking because I didn't see anything like that at the hardware store, and the only other place I saw that was online and I'd prefer not to buy it online if I don't have to.

[vortalexfan]

As for the 23" Zenith TV, I finally got it out of the cabinet, and looked underneath the chassis, and it appears that there are only 7 paper caps in the whole TV Chassis (2 Bumblebee caps, 1 ceramic tubular cap, and 4 brown plastic tubular caps), the rest are either Brown or Yellow Ceramic Disc Caps or Mylar "Brown Drops" and "Orange Drops".

As for the Electrolytic Can Caps, one was a single section cap for the main AC Line Filter (that one tested bad with my ESR Meter), the second was a 4 section electrolytic can that had only one section that tested bad, and the last one was also a 4 section electrolytic can cap that had 2 sections that tested bad.

So as far as the electrolytic cans go, could I get away with just unwiring the bad sections and installing a terminal strip nearby that I could install the necessary replacement caps onto and wire the leads from the dead sections of the aforementioned can caps and then just continue to use the good sections of the original can caps, or should I just replace all of the electrolytics including the ones that still tested good yet in the original cans?

[Electronic M]

Originally Posted by vortalexfan

Ok, well I'll return it then. Where would I get the "sensor safe" stuff then? Would they have it at the Auto Parts store? I'm asking because I didn't see anything like that at the hardware store, and the only other place I saw that was online and I'd prefer not to buy it online if I don't have to.

I've had good luck with Permatex Red from the Advance Auto parts on picture tube bases that have seen use. Be careful, there's 2 different reds and only one is sensor safe.

[vortalexfan]

Originally Posted by Electronic M

I've had good luck with Permatex Red from the Advance Auto parts on picture tube bases that have seen use. Be careful, there's 2 different reds and only one is sensor safe.

OK, I think I may have seen something like that at the local Ace Hardware (which is where I picked up the stuff that apparently wasn't sensor safe) and I didn't realize what it was because I didn't know I was looking for "sensor safe" at the time (I thought I was looking for something else with a similar sounding name.)

[Notimetolooz]

I'm not sure a "gasket maker" product will have the best adhesive properties.
I think a little better choice is this black adhesive. I've used it on other things and it states that it can be used on wires.
https://www.permatex.com/products/ad...esive-sealant/

[Electronic M]

Originally Posted by Notimetolooz

I'm not sure a "gasket maker" product will have the best adhesive properties.
I think a little better choice is this black adhesive. I've used it on other things and it states that it can be used on wires.
https://www.permatex.com/products/ad...esive-sealant/

Yours doesn't have sensor safe on it.

I have one tube that was done in the red several years ago that is still holding on. That tube has probably seen at least 80 hours of use with the red. It started out in my Moto 21CT2 as a replacement for the necked 21AXP, then I got a CTC5 with a good AXP and swapped the CRTs between the two, then I found another mediocre AXP and stuck it in the CTC-5 and since then the permatex RED 21FBP has been sitting waiting to go into a Packard Bell when I get to it.

I just did another 21FBP22 with the red yesterday since the last one did well.

[kvflyer]

Originally Posted by Notimetolooz

I'm not sure a "gasket maker" product will have the best adhesive properties.
I think a little better choice is this black adhesive. I've used it on other things and it states that it can be used on wires.
https://www.permatex.com/products/ad...esive-sealant/

But it doesn't say, "Sensor Safe".

[Notimetolooz]

I don't think there is that much corrosion difference between the two. Either is probably OK. If there is a difference it would be hard to prove because any corrosion difference could take decades to show.
Certainly you don't want to use the type that smells like vinegar ( ascetic acid) as it cures.
The black type has a very strong grip on surfaces, more like a glue.
The gasket maker is something that could be removed and re-made.
Either one requires the surface they are applied to be cleaned well with solvent like strong alcohol or acetone to remove any oil, etc.

[Electronic M]

Originally Posted by Notimetolooz

I don't think there is that much corrosion difference between the two. Either is probably OK. If there is a difference it would be hard to prove because any corrosion difference could take decades to show.
Certainly you don't want to use the type that smells like vinegar ( ascetic acid) as it cures.
The black type has a very strong grip on surfaces, more like a glue.
The gasket maker is something that could be removed and re-made.
Either one requires the surface they are applied to be cleaned well with solvent like strong alcohol or acetone to remove any oil, etc.

You want to use ammonia to clean the mating surfaces. The factory glue responds best to ammonia and if you don't clean the factory glue off it will continue to degrade and undermine anything glued to it.

[vortalexfan]

Originally Posted by Electronic M

You want to use ammonia to clean the mating surfaces. The factory glue responds best to ammonia and if you don't clean the factory glue off it will continue to degrade and undermine anything glued to it.

OK, my parents have some ammonia in their basement, I might have to borrow some.

But no one answered my question about the electrolytic caps in the big Zenith TV, I had asked if it was ok to just replace the bad sections of the multi-section caps and continue to use the good sections of the multisection caps, or if I should just replace all of the electrolytics and be done with it?

[DavGoodlin]

Originally Posted by vortalexfan

But no one answered my question about the electrolytic caps in the big Zenith TV, I had asked if it was ok to just replace the bad sections of the multi-section caps and continue to use the good sections of the multisection caps, or if I should just replace all of the electrolytics and be done with it?

If you find the caps are full-on open with very high ESR, I'm not sure they would reform. It the old days, I usually just bridged a new one across it to see if issue would go away. More importantly, if the cannot charge up to rated voltage using a high-impedance cap tester with an eye tube, just disconnect those sections and replace one cap as needed.

Often just the half-circle (usually the highest value) cap section is suspect as it gets the full DC supply initially before the tubes warm up and begin to draw current.

I usually find one out of four open, showing very high ESR, almost always on the lower values like 2, 5, 10, 20mf etc. Even if ESR is low, you may still find that cap becomes leaky at rated voltage. It probably went bad long ago but a good set like this Zenith might not show symptoms.

[vortalexfan]

Originally Posted by DavGoodlin

If you find the caps are full-on open with very high ESR, I'm not sure they would reform. It the old days, I usually just bridged a new one across it to see if issue would go away. More importantly, if the cannot charge up to rated voltage using a high-impedance cap tester with an eye tube, just disconnect those sections and replace one cap as needed.

Often just the half-circle (usually the highest value) cap section is suspect as it gets the full DC supply initially before the tubes warm up and begin to draw current.

I usually find one out of four open, showing very high ESR, almost always on the lower values like 2, 5, 10, 20mf etc. Even if ESR is low, you may still find that cap becomes leaky at rated voltage. It probably went bad long ago but a good set like this Zenith might not show symptoms.

Well the Main Power Supply Filter Cap (which in these Zenith's, at least the ones I have) is just a single section can seemed to measure what I'm assuming to be either open or shorted as on my ESR tester (one of the small digital readout ones that you would get as a kit online either fully assembled or you would have to assemble yourself) was showing 29pF on the readout with no ESR reading or anything.

The sections that tested good had ESR readings of .77 ohms or less, (those were on the two 4 section cans) and the one 4 section can that had one bad section the bad section showed a lone 29pF readout on the display and no ESR readout, the one that had 2 sections bad also read 29pF and no ESR reading on the display, which like I said I'm assuming that means the sections are open or shorted.

The paper caps in the TV all read pretty close to spot on MFD value wise, but that doesn't mean anything, they could still be leakier than all get out.

[Electronic M]

Originally Posted by vortalexfan

OK, my parents have some ammonia in their basement, I might have to borrow some.

But no one answered my question about the electrolytic caps in the big Zenith TV, I had asked if it was ok to just replace the bad sections of the multi-section caps and continue to use the good sections of the multisection caps, or if I should just replace all of the electrolytics and be done with it?

I did that on my 29JC20 and it shorted or opened a section every 2 weeks after that until the 3rd time I gave up and changed them all.

[Notimetolooz]

It is best to just go ahead and change them all rather than go through the trouble of having to remove the chassis again. Caps are really not that expensive compared to other things that sometimes have to be replaced.

In your question about the flyback cover that is falling apart, you will have to do something to support the centering magnet rings at the very least.
There is a thread somewhere here that show how someone built up a replacement cover for another type of set.
I have also seen a post about someone else that made a new cover using a 3D printer for another set.

[vortalexfan]

Originally Posted by Notimetolooz

It is best to just go ahead and change them all rather than go through the trouble of having to remove the chassis again. Caps are really not that expensive compared to other things that sometimes have to be replaced.

In your question about the flyback cover that is falling apart, you will have to do something to support the centering magnet rings at the very least.
There is a thread somewhere here that show how someone built up a replacement cover for another type of set.
I have also seen a post about someone else that made a new cover using a 3D printer for another set.

You mean the yoke cover? Because that's what fell apart on the 23" Zenith of mine, I unfortunately don't have access to a 3D printer, let alone the design plans for this TVs Yoke cover.