After many hours of toil, here are the completed schematic pages for the Crosley. Now I can begin the electrical restoration with some confidence.

First the 2 pages for the power supply chassis, then I will post the 4 pages for the TV chassis.

http://www.videokarma.org/attachment...2&d=1335570054

http://www.videokarma.org/attachment...3&d=1335570054

And here are the 4 pages for the Crosley TV chassis. Enjoy!

http://www.videokarma.org/attachment...4&d=1335570544

http://www.videokarma.org/attachment...5&d=1335570544

http://www.videokarma.org/attachment...6&d=1335570544

http://www.videokarma.org/attachment...7&d=1335570544

John, that thing is a beast! Large quantities of tubes that are power hungry. I imagine it draws at least as much as a tube-type color set?

Nice job. Let the work begin...

From what I've read about it, I don't think that silicone or any "sealer in a tube" would stop high vacuum leaks: the force involved is tremendous. Others have tried to seal I believe using a special glass melted at the joint, probably not possible in a home workshop.

I'm not so sure about that...

I mean, consider a layer of clear silicone, say even 1/16 to 1/8", on top of an intact metal to glass seam of a CRT. An intact seam. It would seem to me that silicone, which is pretty dense, would have a tough time entering a small fissure or pinhole that would arise in such a joint.

We're talking about a vacuum here. How is hardened silicone going to creep INTO a joint under those conditions? Again, I'm talking about a preventative measure here.:smoke:

Prolly worth a shot...What have you got to lose ? If it saves a truly Unobtainuim CRT, then, it'll be worth the effort.

The problem you will have is that the silicone doesn't adhere nearly well enough to prevent a vacuum leak, the air would just creep under the sillycone and still get in. That's why I think the nickel plating that Bob has done will work, because it's actually a hard coating on the metal ring, as frit is to the glass bell.

I dunno....silicone bonds to both glass and metal very well. If you prep the surface with some lacquer thinner or alcohol it should bond well.

Also, silicone flexes very well, and stands up to high temperatures.:smoke:

If such an easy solution worked, don't you think it would have been tried already?

If I had a dog in this fight, I'd try this stuff:

http://www.pchemlabs.com/product.asp?pid=2629

Yeah, I know about that stuff. Do you think a CRT gets THAT hot? Regular silicone is pretty good at standing up to temperature, I believe...:smoke:

Has anybody tried it?:smoke:

The ones to ask would be those involved with the early television museum project of trying to seal leaking CRTs. I don't think they would have gone to all the trouble with frit glass and such if an easier method would work.

It won't even keep the oil inside my VW engine, there's no way it's gonna keep air out of a CRT! lol

After a glorious time at the ETF convention, its back home and back to work on the Crosley.

First up is the sweep/power supply chassis. A straightforward recap job. Three of the four electrolytic cans were restuffed. The fourth, a single section 500uF/50V was replaced with an axial electrolytic under the chassis, leaving the old can unconnected but in place for cosmetics.

http://www.videokarma.org/attachment...8&d=1336779880

Now on to the main TV chassis......

I thought the Dumont Sovereign was the only 30" set back then just goes to show what I don't know.

I am guessing that the DuMont 30" set was the only one produced in any quantity. Dumont made two production versions of the 30" set.

As I have not been able to find any documentation published on the Crosley, and the Sweep/Power Supply chassis is put together with nuts and bolts (no rivets), I think the Crosley was produced in very small quantities.

I'd love to have a set with no rivets.

that is i think the first one i have ever seen ,sure is interesting set.

The recap of the main TV chassis is complete. The electrolytic cans have been restuffed. All the silver micas were replaced to improve reliability. A goodly number of off value resistors were replaced.

http://www.videokarma.org/attachment...1&d=1337286425

All of the AC wiring needs to be replaced, and tubes still have to be tested. And the little UHF converter chassis needs to be recapped. And when all that is done, I still have to swap out the CRT. So still some work to do.....

Nice work, John.

Yeah-This brings up a point-Do WE do a better job re-doing this old stuff than when it was originally made ? I know in certain cases, we have better components-eg capacitors-now than they did "Back then", but I'd argue that we put an extra value of "Love" into these old sets that wasn't there when they were made.

No doubt about that. When restoring or even simply repairing a set, we have the luxury of taking as much time as we want to make sure that things are done "right". This simply wasn't possible for production workers on an assembly line.

We can also choose to use better quality parts than the original manufacturer did. This covers cases where either the technology has vastly improved (capacitors), or where the original design cut corners to save money (higher wattage resistors to replace ones which have overheated and drifted).

In addition we have some history and knowledge about the pros and cons of the TV and can try to correct some issues.

Carl

Nice work John! Wish I could have spent a couple days with you last week. Has the cabinet came back from the refinisher?

Bob, I am still waiting on the Admiral 21" color and Airline 7" TV cabinets to come back.

Chuck A will be by this weekend, and I plan to try and swap out the Crosley CRT and power it up for the first time.

So exciting watching a 60 year old piece of electronics coming back to life after a long long slumber!

The first plug-in after capacitor replacements is always a feeling of anticipation to me.

PUH-LEEZE Be Careful !! You guys really oughta have me down there, wringin' my hands & worryin' for you...

As to weather we improve things or not.

I feel there are several factors where we can "improve" things when restoring/repairing these old sets.

Higher quality components, for Korean War Era 1950-1953 sets, wartime restrictions caused some components most notably resistors to be of lower quality, today's resistors are of MUCH higher quality if we chose good ones.

Capacitor tech has improved greatly in lets say the last 80 years (going back to 20-30's AC radios here) not only are they MUCH more stable and reliable and also take up MUCH less room, making subsequent repairs easier because of the extra space.

TSB's In many cases we have access to not only schematics through Sams and Riders but we also have Technical Service Bulletins (to use a GM term) from the maker to implement production changes and improvements.

Enhancements, we also have the opportunity to add things to earlier or less expensive sets that where never designed in them in the first place DC restoration is an example, and possibly extending video bandwidth on sets such as the post 1954 RCA B&W ones that had a 2.8 mHz bandwidth. Or even crazier stuff like direct AV drive or even component inputs!

Oh and lets not forget the biggest thing REVERSING BAD and BUTCHERED repairs!

All in all I think we make these wonderful sets even better.

Matt

The old sets we love to work on and devote much time to were manufactured on an assembly line, so the faster they were turned out the more money the mfgr. made. I doubt the old sets were assembled, tested and boxed in more than a few hours--may be far less, so there was no love for these sets at the factory, only for the bottom line.

The Cliff, who spent the weekend repairing and now listening to a 70 year old Philco console radio that was my dad's. It looks like a friendly fireplace in a dark room.

Cliff,

Do I see PreWar FM on that set?

Matt

I think you have to separate the management from the the rest of the team before making such a broad-brush comment about ALL of us production workers. Managers cranked the production numbers as high as the workers could bear sometimes, but there were, and still are people who are proud to put their name on their work. Don't you take pride in your work? When I was a biomedical mfg. tech, I had to get it right, lest someone cash in their chips while being monitored or defibrillated by something I said was okay to ship.

Even some company founders had a customer-comes-first attitude. Find a copy of A First-Class Job about the life of Frank Murphy (of Murphy Radio in the U.K.) and see why his company's products are so revered among collectors. Not every manager in an expensive suit bowed to stockholder or Wall Street pressure, and tin-plate ladder-climbers often had strong union pushback when their blind ambition made life unbearable for the line workers.

And as far as better parts available, I feel the poly-film-dielectric capacitor was a great replacement for the paper-in-oil caps of the early 20th century. Precise resistors are readily available and cheap nowadays, but the ones available back then usually lasted a long time, and I prefer the look of a shiny A-B or Ohmite to those pale, ugly dog-bones you get off the boat.

And noone has been able to explain on here why I need low-ESR caps when the original versions perform just fine. Just sayin'...

Just to follow up on the idea of sealing a CRT leak with caulk --

NO polymeric material is a good long term vacuum seal. Every plastic or rubbery material known has a finite permeability to gasses, including the constituents of air like nitrogen, oxygen, and water vapor. You can't even keep humidity out of enclosure with a polymeric mareial, let alone keep a high vacuum over time.

For a good vacuum seal, you need to use metal, glass, or ceramic. There is a reason why you never see any other materials used on something that needs to hold a high vacuum over extended periods of time.

Yeah, that was my brain-child. I thought a high grade clear silicone bead was air tight, and that it would be held in place, or not disturbed, by vacuum pressure drawing it tight to the seam, if and when a leak did transpire.

I know about their shortcomings in the automotive world, but that involves OUTWARD pressure, not inward.:smoke:

When I restored my RCA CT-100, I applied a product called Vacseal to the 15GP22 perimeter joint, thinking that it might help and it couldn't hurt. I believe John and Bob G. may also have experimented with applying Vacseal and curing in a heat box around that time.

They have done a lot of investigation since that time, and I believe the current thinking is, as Tom says, that you need something like glass or metal. The only proven method is frit glass. The RACS company in France did a frit glass seal on a 15GP22 some time ago, and the last I heard, it was still holding up at the ETF. My 15GP22s are still holding up, too, but that proves nothing, since they didn't leak before I applied the Vacseal.

Phil Nelson

I'm with Bob when it comes to the 15G. If you have one with good emissions and getters, it's probably best to leave it alone. After all, it held vacuum for the last 58 years without any help so why fix what isn't broken. If on the other hand you need a rebuild, the full protocal of leak sealing ought to be applied whether it was still under vacuum or not. As proven by the rebuild attempt of John's under vacuum tube, leaks can pop up even if you assume the thing was good before. It still took a full 30 days for John's tube to become gassy, so it may start out good and deteriorate. I think in the future, 15G owners will likely opt to have the tube treated with frit regardless if it was still under vacuum or not.

Power up!
 

Chuck A was up over the weekend, so we decided to give the Crosley a try. Saturday evening we swapped out the dud 30BP4 for the spare I had. After a lot of adjusting and hooking things up, we connected the variac and brought it up. Nice aucio, but that was all. No high voltage. Kind of a let down. We called it quits for the evening.

Next morning we put the 2 chassis, yoke/focus coil assembly and speaker on the work bench and hooked it all up. First discovery was a blown fuse (which I had tested good earlier). We replaced it and began looking for high voltage.

But here is where I made a really stupid error. Using my B&K HV probe which is a 1000:1 divider, I misread the meter. It was showing voltages (at various times) between 1.1 and 2.0 volts. I was calling this 11K - 20K volts, and we spent the whole day trying to figure out why the high voltage was low and unstable. It would go from 15-16KV down to 11KV or less as thing warmed up. Swapping tubes, checking wiring, freeze spray, nothing we tried was any use.

Chuck A departed back down to south Florida in the morning. Later that afternoon I sat down to have another go at it. Apparently my brain was actually working, and I realized that the meter had been telling us that there was ONLY 1.1-2.0 KV! And yet, using a screwdriver, one could get a big purple arc from the plate of the first 1B3 in the HV doubler. I immediately realized that this meant the rectifiers were not working, probably because the filaments were not being lit. The tubes derrive their filament voltage from the sweep flyback, not the HV flyback. I put two solid state 1B3 replacements in and go 28KV. Hooray!

A check of the bias on the two 6BG6s driving the sweep flyback revealed no screen grid bias. The 3K ohm 10W bias resistor (which had ohmed as good earlier) was open. With a replacement installed and the 1B3s back in, I got a robust 20KV. After things warmed up, it settled at 18KV plus.

I tested all the tubes on the TV chassis, and found none to be bad. I reinstalled everything back in the cabinet, and after some adjusting of the yoke and focus coil and centering lever, gat a very presentable picture. I actually looks much better than these photos indicate.

http://www.videokarma.org/attachment...1&d=1337816915

http://www.videokarma.org/attachment...1&d=1337817036

http://www.videokarma.org/attachment...1&d=1337816915

This CRT works even better than I hoped. Plenty of brightness and contrast. Next time Chuck A is up, we will do setup on the V&H size and lin, and play with the pincushion magnets.:banana:

I am jealous.....Nice Set!!

Thats one handsome TV set! I've never seen a round screen 30 incher!

I'm in love...Hats off to you guys !