Hey, Guys I recently picked up an Admiral Model L2711 Tv with the 20L8M chassis. I made a solid state 5U4, disconnected the high voltage cap from the flyback, and brought it up on my Variac over a period of about 10 hours in 5v increments starting at 25V. Unfortunately, I don't have any B+. I've been watching a lot of Shango lately and I want to try and Resurrect this set before I do a full recap. It would be nice to actually see it work and then check it after each cap I change rather than shotgun it and try to figure out what I've done wrong as I've done in the past.

I've tried to find it in Bietmans for 61-63 and it's not in there. Does anyone else have a schematic? I've had trouble with Sams lately. I got the schematic for my RCA and couldn't read it. I had to call and complain, and wait for them to rescan the original. I know it would make it much easier to have the schematic instead of clipping one lead of every cap at a time and testing with my Heathkit C3, the other option I thought of was using Audio like he does in some early videos.

What do you guys think?

Its nice to see someone use what I think is the best approach.
You are 100% right. The shot gun method often ends in a
more broken set.
Sams is your best option. There are a few still selling original
paper. I do but its too old for my coverage.
These admirals were rugged sets & if it has a good CRT should
come out very nice.

73 Zeno:smoke:
LFOD !

Hey, Guys I recently picked up an Admiral Model L2711 Tv with the 20L8M chassis. I made a solid state 5U4, disconnected the high voltage cap from the flyback, and brought it up on my Variac over a period of about 10 hours in 5v increments starting at 25V. Unfortunately, I don't have any B+. I've been watching a lot of Shango lately and I want to try and Resurrect this set before I do a full recap. It would be nice to actually see it work and then check it after each cap I change rather than shotgun it and try to figure out what I've done wrong as I've done in the past.

I've tried to find it in Bietmans for 61-63 and it's not in there. Does anyone else have a schematic? I've had trouble with Sams lately. I got the schematic for my RCA and couldn't read it. I had to call and complain, and wait for them to rescan the original. I know it would make it much easier to have the schematic instead of clipping one lead of every cap at a time and testing with my Heathkit C3, the other option I thought of was using Audio like he does in some early videos.

What do you guys think?
It looks like it has a separate safety glass!
There isn't that many 27" sets around. 23's and 24's were very popular.
The last 27" I saw was a '65 Magnavox and it was solid state. I replaced the CRT with a rebuilt. It was the first solid state B/W set.

It does have a separate safety glass and I can't tell if it has mold in between or just the glue is separating. The picture with the cardboard underneath is after I cleaned it. If I have all that mold will it be easier to clean up the cataract?

Is it color? That would be the reason for the "Cataract" on the picture tube.

It appears to be in Sams folder 593 and I see two sellers on eBay. Downloading from Sams is about the same price but others have complained about the quality of downloads. I have not downloaded any so I can't confirm/deny.

Hey,
Nice set. Real nice actually.

Yeah with SAMS photofacts the hard copies are king!

Which CRT does this use? I only ask because I have a few massive yokes in storage which would only fit a large black and white tube such as a DuMont royal. I am planning on itemizing all of my stored parts soon. Lots of treasures in there.

Hey,
Nice set. Real nice actually.

Yeah with SAMS photofacts the hard copies are king!

Which CRT does this use? I only ask because I have a few massive yokes in storage which would only fit a large black and white tube such as a DuMont royal. I am planning on itemizing all of my stored parts soon. Lots of treasures in there.


It's a 27YP4 tube. Mine is marginal so if you have one to sell I'll be happy to buy a tube from you.

I know it would make it much easier to have the schematic instead of clipping one lead of every cap at a time and testing with my Heathkit C3, the other option I thought of was using Audio like he does in some early videos.

What do you guys think?
I hope you are actually reading the value printed (or in the case of Sprague Bumble Bees color coded) on to the body of the capacitor instead of using the C3 to tell you value. I've seen plenty of paper caps develop high ESR and measure 2x their labeled capacitance.


Is it color? That would be the reason for the "Cataract" on the picture tube.


There were NUMEROUS monochrome CRTs in the early 60s to early 70s that used bonded safety glass the same way color CRTs did. I've owned at least 5 bonded safety glass monochrome CRTs and removed a cataract on one. The early 60s Zenith monochrome tubes are the worst because they do something no color tube ever did...They made the safety glass a deep dish such that not only does the glass cover the face of the CRT it wraps roughly 2" around the sides of the tube such that you can't get a guitar string in and the wedge method won't work because the wedges don't lift the glass off the screen.

So I turned the set on just now and started poking around with my meter trying to see what capacitor wasn't producing I poked the circuit breaker and all the sudden the set came on. Granted the spacing isn't great but here it is displaying crosshatch. Unfortunately I did have to hook the brightener up to get it this bright but I'm wondering how much of that is the cataract?

I think that is mold in between. Do you think it will be easier to remove the lense? Because the seal jas been breached? I've never done it before and I'm very intimidated by the idea of removing it. I wish there was someone in NJ who I could take it to.

Please don't disregard the post above, but I shut the set off and turned it back on. The brightener that was on the tube started to buzz loudly, and I only got a dot on the screen Is that common? It's been on this set since the early 70s when it was put away. Does it have caps that dry out inside? I hooked everything back up without it and the TV works again but obviously the picture is dimmer.

You have focus problems and vertical problems based on your picture of it running.

Cataract removals are doable. You can see how I do them in this video. https://m.youtube.com/watch?v=F8Wfg1I1Z8Y

It seems to me the brightener could be defective (may have been for years, if it has been on the tube since the 1970s). Removing the brightener must have removed the short or whatever it was which was killing your vertical sweep if you now have a picture again, although if you lost both sweeps at once (but still had HV, which of course means the horizontal sweep must still be working) with the brightener in the circuit, that would seem to indicate the brightener itself is indeed defective.

Your TV also, obviously, has a weak CRT, if the set has had a brightener on the tube for who knows how long. However, before replacing the CRT (I don't know if 27" CRTs are still made today), I would try replacing the brightener since, as I mentioned, it may have an internal short which is killing the vertical sweep. If both sweeps work with the brightener out of circuit, that seems very likely.

Of course, if you are getting only a bright dot in the center of the screen, turn the TV off immediately, and keep it off until you find and correct the problem. Otherwise, the dot will burn itself into the phosphors in the center of the tube, similar to "ion burns" CRTs used to get years ago when the vertical sweep quits. Once this happens, of course, the tube will be ruined forever, as there is no way to repair or undo the damage vertical sweep failure will cause.

Okay so the brightener is definitely bad I hooked it up to my CRT tester just to see what would happen and as soon as I put heater voltage to it it started buzzing away like a bad Transformer. I have two questions one is my brightener says I.E.H. Manufacturing Company New York New York parallel picture tube brightener and then it says cr64 5 wire cr64s 6 wire. I don't have a catalog to look up the brighteners I see on eBay. Is that CR number standard for all brightness?

I was reading through the video Karma page and trying to learn a little bit about the brighteners. A few posts said it's better to rejuvenate the tube after 4 hours of use then keep a brighter on it, is that true? And I see a lot of people don't like the B&K testers for rejuvenating, they're more partial to the Beltron because it is less of a burst. Mine has three rejuvenating settings called Dyn -Low, Med, and High on it is it still has rough as the earlier ones?

It's a 27YP4 tube. Mine is marginal so if you have one to sell I'll be happy to buy a tube from you.

I don't have any 27" tubes, that I know of. However I have tons of yokes and other parts for the bigger sets. Wish I knew of a new CRT source for you. The big monochrome tubes are pretty scarce.

Brightener has 60cy buzz. Take it apart & probe with plastic. Find a sweet spot & shim it.
More opinions on rejuve than there are weak tubes. I only used modern
B&K, Sencore or Viz. Beltrons were a tester that also had a big
marketing push behind it.
The lower you go the less risk of killing the CRT.

73 Zeno:smoke:
LFOD !

So good news I rejuvenated the tube on Dynamic low and it went from a very weak reading to almost a full reading. The picture looks better than it did with the brightener now. Looks like it's time to start buying capacitors.

Remember a few at a time then test as you go.
Good luck
Zeno:smoke:

So good news I rejuvenated the tube on Dynamic low and it went from a very weak reading to almost a full reading. The picture looks better than it did with the brightener now. Looks like it's time to start buying capacitors.

I destroyed a weak GE 21ATP4 by weld-shorting elements.
Using my BK445 on dyn hi when it barely moves the needle on emission at 12 volts on filament,
white hot and no cathode dust left. Now a neon-glowing on both halves with a short
Using Dyn Hi is the last desperate move after dyn lo and dyn med failed to restore emission.

Admiral BW tubes from 50s-60s were always decent and responded to a light touch :thmbsp:

So glad you had a good experience. I have a 27" Muntz with a no-name rebuilt 27EP4 and a Beltron in for repairs.

I destroyed a weak GE 21ATP4 by weld-shorting elements.
Using my BK445 on dyn hi when it barely moves the needle on emission at 12 volts on filament,
white hot and no cathode dust left. Now a neon-glowing on both halves with a short
Using Dyn Hi is the last desperate move after dyn lo and dyn med failed to restore emission.

Admiral BW tubes from 50s-60s were always decent and responded to a light touch :thmbsp:

So glad you had a good experience. I have a 27" Muntz with a no-name rebuilt 27EP4 and a Beltron in for repairs.




Your experience is exactly why I was so afraid to try and rejuvenate my tube. Out of curiosity do you know who made the tubes for Admiral in this era?

Your experience is exactly why I was so afraid to try and rejuvenate my tube. Out of curiosity do you know who made the tubes for Admiral in this era?

They had several firms that they bought their CRT's from.
It looks like the one you have is a Thomas, IIRC EIA 672.

So I hooked a VCR To the Set and its working surprisingly well, with the exception of being a little blurry. I'm wondering if that is just because I'm looking at the image through a lense that looks like a glass of milk. I've watched a ton of cataract videos this week. It seems I have the RCA style Cataract. I'm probably worrying too much about this, but I'm afraid to ruin an unobtainable tube. It seems there are 2 methods to remove the PVA either a ton of heat, or soaking it in water or vinegar and water for months on end. What is the best way to do it? I read one post that guy used those heat lamps they put food under to get it loose, I've seen people use plastic bags and put it in the sun, I've seen halogen lights, is there a fool proof way? Has anyone tried soaking it in a solvent first to soften it? Like Acetone, gasoline, diesel, laquer thinner, etc. Then apply heat? Or maybe pick out all the edges or do the guitar string like Tom C then soak it so the water gets in easier? I really think I'm over thinking this, and probably being over paranoid, but I really like this set and I'm afraid to implode or ruin that tube some how.

Your tube seems to have a focus problem more so than a cataract problem based on what I see in the pictures. I'm not saying the cataract isn't contributing to it (it surely is), but I would probably try to electrically improve focus first.

For an RCA cataract removal there's safe and there's effective which are 2 different things. The water method is very safe, but unless the tube has delaminated all or almost all the way to the center has been completely ineffective when I have tried it. The guitar string method is safe and on all Zenith and maybe 10% of RCA tubes effective. Ninety percent of RCA tubes seem to have too hard of a glue to be effective. The heat method is dangerous but highly effective....The danger is not using enough finesse. If the heat on the face is uneven and applied too fast (should be heated gradually over hours of time) the tube will fracture or implode. Also wedges are needed wit the heat and if you push them in too hard it's easy to crack the safety glass...If you crack the safety glass you can still salvage the tube but you have to suffer the glass shard hell of chipping off the safety glass with a hammer and chisel (did that probably 10 times before I got a heat gun which combined with the sun got me to a point where I could reliably get the safety glass off intact).

Others probably have their own oppions.

Your tube seems to have a focus problem more so than a cataract problem based on what I see in the pictures. I'm not saying the cataract isn't contributing to it (it surely is), but I would probably try to electrically improve focus first.

For an RCA cataract removal there's safe and there's effective which are 2 different things. The water method is very safe, but unless the tube has delaminated all or almost all the way to the center has been completely ineffective when I have tried it. The guitar string method is safe and on all Zenith and maybe 10% of RCA tubes effective. Ninety percent of RCA tubes seem to have too hard of a glue to be effective. The heat method is dangerous but highly effective....The danger is not using enough finesse. If the heat on the face is uneven and applied too fast (should be heated gradually over hours of time) the tube will fracture or implode. Also wedges are needed wit the heat and if you push them in too hard it's easy to crack the safety glass...If you crack the safety glass you can still salvage the tube but you have to suffer the glass shard hell of chipping off the safety glass with a hammer and chisel (did that probably 10 times before I got a heat gun which combined with the sun got me to a point where I could reliably get the safety glass off intact).

Others probably have their own oppions.
Try removing the CRT and investigate. All the 27" sets of that era had a separate safety glass. The 27" tubes were falling out of favor at the time.

There were NUMEROUS monochrome CRTs in the early 60s to early 70s that used bonded safety glass the same way color CRTs did.

I'm embarrassed to say for all the years in the trade, I never knew there were BW CRTs with bonded faceplates. No doubt they went through the shop, but for issues other than jug replacement.

We had a B&W 23" Sylvania, purchased in 1960, with a 110 deg bonded safety glass CRT. I guess cataracts weren't a problem back then as most CRTs didn't last long enough to form cataracts. Good TV, but the original CRT only lasted 4 years.

Here's a good question. What did CRT rebuilders do with the bonded safety glass during the rebuild process? Did the just leave it alone during all the baking? I don't remember ever reading where they removed the safety glass, rebuilt the CRT and then re-applied the safety glass.

Curious minds want to know....

I believe neither type of bonding material would survive the baking.

If heating the face just enough to remove the bonding is dangerous, it seems the baking process would be a disaster for the tube as well as the bonding material, no?

I don't know if all rebuilders had a way to rebond the faceplates, maybe only the OEMs? It would be interesting to find out

I believe neither type of bonding material would survive the baking.

If heating the face just enough to remove the bonding is dangerous, it seems the baking process would be a disaster for the tube as well as the bonding material, no?

I don't know if all rebuilders had a way to rebond the faceplates, maybe only the OEMs? It would be interesting to find out

I agree.The bonding material may not and probably would not survive any kind of removal procedure involving high temperatures.

As rare as 27" CRTs seem to be, I wouldn't even try to remove the safety glass; there is too great a risk of damage to the tube. I don't know if the Admiral TV you have would or could use a smaller tube, say 23 inches (differences in things like deflection angles and, of course, the physical size of the tube; the latter could be a problem since the mask, not to mention the mounting itself, would be four inches too large, leaving an unsighly gap between the edges of the tube and the CRT mask itself), but it might be worth a try if you can somehow compensate for the difference in screen sizes.

BTW, yours is the first TV I have ever seen with a 27" CRT (I have never seen a set with a CRT this large in person in my life). Most televisions I have ever run across used CRTs no larger than 25 inches. (I once had an Admiral "Microgrid 390" 23" console TV, but this set had the largest CRT I ever saw in a b&w TV.)

Why Admiral decided to use a 27" CRT in any of its TVs is a mystery to me, unless they wanted to see how well a set with a tube that big would sell in the 1950s; after all, no other TV manufacturer, except perhaps DuMont, ever came out with a TV using a CRT this big.

My best guess is those sets did not sell very well, which could have been one of several reasons Admiral went out of business when it did. It has been mentioned in VK that Admiral televisions had a lot of problems, not the least of which had to do with HV regulation, even in their b&w sets. I had an uncle who replaced a 23" Sylvania console TV with an Admiral 17" (IIRC) color portable in the 1970s; the latter seemed to work well, with no major problems I was ever aware of. This may have spoken well for the quality of Admiral TVs at that time, but the quality of these TVs went downhill fast shortly thereafter.

This could and probably would explain why the company went out of business when it did, although there was a Japanese or Chinese firm which might have tried to revive Admiral in the early '80s. This firm was known as AOC, for Admiral of China. I don't think AOC's televisions (if the company ever made a color set) were much good, however; if they had been, AOC might still be in business today.

IIRC Magnavox offered 27" B&W TVs for a number of years in the 1950s.

I currently own a 36" Sony Trinitron. Talk about heavy and bulky. It weighs more than I do!

IIRC Magnavox offered 27" B&W TVs for a number of years in the 1950s

Zenith made a nice 27 inch set in the mid 50s.
http://www.tvhistory.tv/252KA21A5.jpg

jr

Interesting.... Look at the model name of this Zenith: Sovereign.

I had a friend who worked for Video Display in Atlanta rebuilding tubes. He said the safety glass was removed and the tube fitted with a steel safety band after the rebuild process in stead of replacing the separate glass. You could pre-order a tube with a safety glass for an additional charge if you wanted. I did this several times, those tubes now have the RCA type cataract.

Zenith made a nice 27 inch set in the mid 50s.
http://www.tvhistory.tv/252KA21A5.jpg

jr

I had forgotten about that 27-inch Zenith; thanks for refreshing my memory. Now that I think of it, however, I do remember seeing full-page color advertisements for these TVs in National Geographic magazines of the 1950s.

I had forgotten about that 27-inch Zenith; thanks for refreshing my memory. Now that I think of it, however, I do remember seeing full-page color advertisements for these TVs in National Geographic magazines of the 1950s.

Zenith and DuMont were the only TV manufacturers I knew of that offered 27-inch televisions, although I saw a post in this thread which stated Magnavox and Zenith offered 27-inch TVs, probably in the '50s. Large TV screens were falling out of favor with viewers by the end of the 1950s, as I don't remember seeing any ads for TVs this large in magazine ads of the 1960s to the end of the NTSC TV era.

How times have changed. It is now 2022 and the large TV screen has returned, although by "large" I am referring to today's HDTVs and projection televisions, many if not most of which are 32 inches or larger. In TV's early days, the entire idea of 27-inch CRT TVs, IMHO, was to make TV movies look as large (or at least come close in the 1950s) as they would in a motion-picture theater; the effect may have been lost, however, on other types of TV programming unless, again, the intent was to make the picture look almost literally larger than life.

Today's HDTVs are excellent at creating this effect (the larger the screen, the better(!)), which probably scares young children half out of their wits. I have a 32" flat-screen HDTV which makes a beautiful picture, but the sheer size of the screen makes just about everything (including, of course, those hideous scenes of violence on the evening news, not to mention violent scenes in prime-time TV shows and movies) look gigantic, especially on very large screens, say 60 inches on up to 70 inches or more(!).

my set is from 1962 so it's not just a 50s thing

A quick perusel of the tv history site ( http://www.tvhistory.tv/1950-1959.htm ) turned up a number of monochrome 27 inch sets in the 50s:

Admiral, Arvin, Capehart, Crosley, Emerson, Hallicrafters, Hoffman, Magnavox, Motorola, Muntz, Packard-bell, Philco, Setchell Carlson, and Zenith.

Oddly, no RCA, GE, Westinghouse, or Sylvania 27 inch monochrome models were found.

Many Dumont 30 inch sets were likely converted to 27 inch when the 30BP4 became unavailable.

jr

A quick perusel of the tv history site ( http://www.tvhistory.tv/1950-1959.htm ) turned up a number of monochrome 27 inch sets in the 50s:

Admiral, Arvin, Capehart, Crosley, Emerson, Hallicrafters, Hoffman, Magnavox, Motorola, Muntz, Packard-bell, Philco, Setchell Carlson, and Zenith.

Oddly, no RCA, GE, Westinghouse, or Sylvania 27 inch monochrome models were found.

Many Dumont 30 inch sets were likely converted to 27 inch when the 30BP4 became unavailable.

jr

RCA made a 27 inch set in 1953. It had a 27MP4 rectangular metal cone CRT in it! I installed a rebuilt CRT. The big metal CRT's were only guaranteed for 6 months by the rebuilder!

RCA made a 27 inch set in 1953. It had a 27MP4 rectangular metal cone CRT in it! I installed a rebuilt CRT. The big metal CRT's were only guaranteed for 6 months by the rebuilder!

Much thanks for the info! I remember seeing a 27MP4 years ago in a collectors’ stash and thinking that it must have been removed from a RCA set, but never found out for sure.

jr

Ok guys I removed the Cataract. I can't believe how easy it was. I'm starting to wonder if it's just an Admiral thing. I was watching a video where the same thing happened to shango. I put the tube outside on the garbage can, and started to pick at the glue to put my wedges in, and then the whole lens just broke free. So after a few hours of cleaning and siliconing, the tube looks great. I put it back in the TV as soon as the silicone dried to keep it from getting broken.

Here are some pics along the way

Also, the tv is still on stock caps, so it's not perfect but it's working.

I tested all the tubes, and changed 3 that had bad grid leakage once they heated up. I need to order the one for the sync separator and one of the tubes in the tuner and then they should all be in good shape. This set must have more miles than a New York City taxi, half the tubes have been replaced already, not to mention the combination of cigarette gunk and dirt inside. It took me a while to get everything clean. Also, I think my heathkit pattern generator needs some caps so excuse the test pattern. But here's everything. The next step is recapping the vertical section

By the way, how do I put the legs on by myself, this set weighs a ton.

...By the way, how do I put the legs on by myself, this set weighs a ton.

I think putting the legs on would not be too hard by turning it on one side first; but the dangerous part could be trying to stand it upright as it is temporarily pivoting on two of the legs. (How sturdy are the legs?) Maybe attach something sturdy and slightly taller than the legs to the bottom before rotating it upright, getting it to turn and rest on the additional support first and then tilting it slightly onto two legs to remove the added support?

Sounds like the entire face was cataracted...I LOVE it when RCA style cataracts are that bad as it often requires zero effort to fix. I've only encountered it a few times and I think all sets were from a wet TV shop basement in Indiana. One of the roundy tubes from there I picked up, walked 10' with the tube face down and the safety glass simply dropped off.

How long are the legs? If under 12" lift the light side of the cabinet and screw 2 on, then lift the other side and screw on. If significantly longer than 12" get 2 shorter legs than the set you're going to install and install them on one side install longer legs on the other side then swap the short legs for a matching set.
The problem with installing legs with the set on it's side then rotating it over is if you and a buddy aren't strong (and non-lazy) enough to not touch the set to the ground while rotating it, odds are you'll ballance it on 2 of its legs through a good portion of the rotation and it's not unheard of for those screw on legs to snap when supporting lateral forces equal to the sets weight, then other bad things happen. Ask me how I know...

Sounds like the entire face was cataracted...I LOVE it when RCA style cataracts are that bad as it often requires zero effort to fix. I've only encountered it a few times and I think all sets were from a wet TV shop basement in Indiana. One of the roundy tubes from there I picked up, walked 10' with the tube face down and the safety glass simply dropped off.

How long are the legs? If under 12" lift the light side of the cabinet and screw 2 on, then lift the other side and screw on. If significantly longer than 12" get 2 shorter legs than the set you're going to install and install them on one side install longer legs on the other side then swap the short legs for a matching set.
The problem with installing legs with the set on it's side then rotating it over is if you and a buddy aren't strong (and non-lazy) enough to not touch the set to the ground while rotating it, odds are you'll ballance it on 2 of its legs through a good portion of the rotation and it's not unheard of for those screw on legs to snap when supporting lateral forces equal to the sets weight, then other bad things happen. Ask me how I know...

It really was completely cataracted here's a pic of the lens and the PVA. The interesting part was the PVA was rubbery almost like rubber cement, and the Lense was much bigger than the tube. There was probably 1/8 inch overlap on top and bottom. Also the gray screen on the tube has few tiny little holes in it maybe 3 or 4 of them. Almost like the seat in a smokers car. Not big cigarette burns but the tiny pin holes from the ash. Also when I shut the set off there's a tiny little dot on the screen that lasts for about 2 minutes. I've been turning the brightness down after shutting it off. So far it's been running for about 2 hours straight with no real issues, but I shut it down and unplugged it for the night. There's a light hum bar that comes and goes, and an occasional twitch in the screen, it almost pulls to the right slightly like the vertical hold is a little off for a split second then is fine for a while.

The legs are probably 6-8 inches long. I was afraid they might break or the brackets might bend putting 2 legs on at a time but ill give it a shot.

It looks great on it's legs.

I somehow missed this thread earier. That Admiral cleaned up really nice.

Can confirm Maggy had a 27" B&W. We had one from the pre UHF mandate apx 1963. Jug went soft & the old man got a Zenith console color
to watch the '67 Red Sox in the world serious.
LEGS put set on side, put on two legs. Tip up on the two legs, lift the other side
& screw / twist on last legs.
If you got 2 men put all legs on & flip !

73 Zeno:smoke:
LFOD !