The 30" CROSLEY TV RESTORATION
 

The next big project (literally) is the restoration of my 30" Crosley TV, featuring the 30BP4 CRT. I have had this set a number of years now, and it has been lurking in the corner of my garage hiding under a big red bedspread. I had decided not to take it on until now for three reasons. First, its 30BP4 is a dud. Second, top of the cabinet is in poor condition, and will need refinishing. A skil which I do not possess, and am not likely to acquire. And third, I have never been able to find documentation for the set.

http://www.videokarma.org/attachment...1&d=1334514986

http://www.videokarma.org/attachment...1&d=1334514986

http://www.videokarma.org/attachment...1&d=1334514986

With the recent news of RACS in France possibly closing their doors this summer, I contacted RACS through Jerome Halphen to see if they would rebuild the tube. Alas, the word came back that either the tube would bee too big to fit in the over, or if it did fit, it would be too close to the heating elements. This news finally motivated me to do something I have been putting off for a very long time.

I have a spare 30BP4 up on a top shelf in the garage, but it tests quite weak on my trusty Beltron CRT tester. But the 30BP4 in my 30" Dumont Royal Sovereign does not test all that good either, and it makes a presentable, though not very bright, picture. So I decided the only thing to do was to pull the spare 30BP4 down and use the DuMont set to drive it and see if it was worth the effort to use it for the Crosley set.

Being a lazy guy, I really did not want to demount the CRT from the DuMont and install the spare. So I used the bottom canister from the shopvac as a test stand and put the CRT face down on the canister.

http://www.videokarma.org/attachment...1&d=1334514986

This worked out very nicely, and after a bit of configuring, I powered it up. Nothint. I adjusted the ion trap, still nothing. I checked the HV; a generous 17KV. So I flipped the ion trap over and after a bit more adjusting.... hot dog!

http://www.videokarma.org/attachment...1&d=1334514986

It may not be the brightest tube, but it is good enough. So I made the commitment to take on the Crosley. I made another attempt to find documentation for the set, checking (again) Riders and Sams with no luck. The Model # on the set is E-30 COBU. I have a marketing brochure which shows an artist line drawing of the set, with the Model # EU30COBU (or EU30COMU).

If any of you out there has any info on this set, I would appreciate hearing about it. To be continued....

Continuing... I decided to pull the sweep/power supply chassis and examine it, as it looked unusual. It turns out to be a rather unique configuration,
with separate transformers driving the sweep and HV. I also noted that the whole chassis was put together with nuts and screws, no rivets.
It also has no tags, labels, ink stamps or markings of any kind.

http://www.videokarma.org/attachment...1&d=1334516586

http://www.videokarma.org/attachment...1&d=1334516586


The TV chassis is clearly a more conventional production chassis, though some sort of a modification of what was probably a standard B&W production chassis.
It uses rivets, but once again, has no stamps or markings, other than one little paper label which proudly proclaims the chassis is union made.
All of this leads me to think I will likely not find any documentation for the set.

http://www.videokarma.org/attachment...1&d=1334517000

As I would be a bit reluctant to start recapping the set without a schematic to fall back on, I resolved to trace the wiring and generate a schematic.
Here is the result. The only unknown I found was one crisyp carbon comp ½ watt resistor, shown as R? on page 1, in the B+++ side of the primary of T1.
Does not look like it will be any trouble to S.A.T. a value for it.

I have reposted the two power supply schematic pages in a later post in this thread.

Next, I will generate a schematic for the TV chassis, containing the RF/IF/video/sync/V&H oscillators. To be continued....

John, this is all very interesting! I always thought that the Crosley was a rebadged Dumont. Am I to understand that this set does not share the same chassis as the Royal Sovereign? Also, very nice to see one of these sets in the flesh. I have only ever seen print ads for the Crosley, never the real thing. Do you know of any other collectors that own a 30" Crosley?

leadlike, as you may know, the Royal Sovereign came in two versions. The RA119A featured a RF HV regulated supply, a continuous tuner, and a very deluxe design (as DuMont was wont to do). The second version, (my set), the RA119B1 has a conventional click tuner, flyback, and a very pedestrian design. The Crosley design is their own. The TV chassis is very similar to some other Crolsey B&W sets of the same vintage, but the HV supply (I believe) is unique. I am really looking forward to getting it restored and see how it performs.

Zowie!!!

If it makes that kind of picture without any recapping, it should be an easy restoration. Just keep your forklift handy :)

For such a rare item, I would definitely look into having the cabinet done. There are quick/easy things that can blend minor boo-boos and improve the appearance a lot, if you don't want to invest in a total refinish.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil, The CRT was being driven by the 30" DuMont chassis (which has been recapped), not the Crosley chassis (which have not been recapped). Still, I foresee no real problems restoring the Crosley, just he usual work of replacing wax paper caps and restuffing electrolytic cans. I WILL have the cabinet refinished.

I get it.

Just looking at that giant red CRT gives me a backache.

Phil Nelson

If it's like other Metal/Glass tubes it probably doesn't weigh all that much but I've never handled one bigger than 16"

The 30" tubes don't weigh very much. I remember KX250rider made a post about handling a Royal Sovereign as well as the crt, and he noted how surprisingly light the metal-glass crt is. Certainly the 16" one I handled out of my Zenith seemed totally featherweight compared to an all glass one.

John, I wasn't aware that Dumont made a "cheaper" version of their Royal Sovereign sets. Kind of disappoints me since I only thought they dropped continuous tuners and robust build quality after Emerson took them over.

As an aside on 30BP4s-so few are found today, and even fewer that test good. Did they have a tendency to deplete their cathodes faster than say, a 12" tube did? They certainly shared the same type of gun, but the 30" had vastly more screen area to light up than any of the other B&W crts ever did.

The 30" tube is big, awkward and scary to handle, but not all that heavy. The tube was stored above my head on a shelf in the garage. The scary part was standing atop a 2-step footladder, embracing the bell of the tube, lifting it to point the neck of the tube past my head and over one sholder, and wobbling back down the 2 steps. Whew!

If you look at the photo of the CRT behind the DuMont, you can see the cheaper version chassis. Very conventional.

As for the life expectancy of the 30BP4, I just don't have any data on the subject. I would speculate that not a lot of sets were made using the 30BP4. Seems like DuMont only produced that tube for 2 year(?). Maybe longer for renewal reasons. Or they may have offered rebuild services. The urban legend is that all the metal cone CRTs had a higher failure rate than the all glass CRTs. Seems probable, but I have not seen any reports or articles on the subject.

Hi John... The "bourbon legend" on the 30BP4 is derived from the 15GP22. And, from what I've heard from those blessed (cursed?) to have had to work with such is almost universal based upon being a metal/glass hybrid. (What was the original hybrid? The mule!)

One thing about the Crosley, have you ever though about trying the IUE local(s) in the Cincinatti area or nearby to other Crosley plants? Perhaps a retiree may be a source of schematcs or at least info...

INteresting idea.... but from down here in Florida, I would not have a clue how to deal with the IUE in Cincinatti.

I have pulled the TV chassis. It appears to be a modified version of their 21" model in Sams 186-3. Going through the video IF, so far it is identical. But I ams sure I will find some differences, and will end up drawing a schematic, as it would be too hard to try and mark-up the Sams to document the changes.

But the 15GP22 has an additional "weak spots" that the 30BP4 does not have... the welded flange on the 15GP22 appears to be the major source of leaks. IMHO, one of the problems inherent in the metal cone tubes is the limited getter flash area, as the metal cone allows only the use of getters in the neck rather than the funnel. Much less getter flash area is obtained.

jr

Wow...This is going to be an interesting restoration project John, will be following this thread for sure! :yes:
The largest black and white CRT I've seen is 25 inches in diameter. I have a couple of TVs that use them and both give a very nice picture.
Cheers
Glen.

The next biggest B&W CRT was the 27"... I think there were at least 4 versions made by various CRT makers.

Nice job on those schematics John. That must have taken a lot of time and patients to trace and draw. Good Job!

Thanks Bob. A great deal of my career as an electrical engineer was spent using various drawing editors to generate schematics and PCB layouts and fun simulations, so this was familiar territory. The program I used was from a PCB fabrication company, ExpressPCB (http://www.expresspcb.com/). They supply free software to drew schematics and lay out 2-sided PC boards. The software runs on a PC, or in my case , on a MAC running PC emulation software. I used this software a few years back to design my 'personal color wheel viewer' that I displayed at the ETF.

Steve McVoy used the same software to generate the schematic of Nick's prototype color TV, and Steve was kind enough to let me use his library of components he had created (tubes etc). This made my job a bit easier.

The software is easy to learn, and easy to use, so if any of you want to draw a schematic and/or lay out a PC board, check them out. They have a pretty extensive library of pre mace components, both analog and digital, and it is easy to create custom symbols and shapes in the schematic editor.

PS I noticed a bunch of errors in the reference designators on my posted schematic. Fixed 'em, will update them the next time I make my next update.

Hi John,

Wow: this is an amazing set. Looks like you are going to have lots of fun with this one. I will stay tuned for more.

I reviewed your drawings and I spotted one thing I cannot figure out. It looks like you specified for V10 a 6BQ6 for the vertical output. The control grid has a 500ufd/ 50volt capacitor on the control grid I cannot make sense of. The 500ufd would have to me been more appropriate as the cathode resistor bypass capacitor.

Terry

John, your reference to the Express PCB Schematic software piqued my interest. I downloaded it and it runs on my Linux desktop too using "Wine".

One thing I did notice is that it lacks Vacuum Tube symbols. Did you custom create those symbols or is there a library I can import?

Thanks

Carl

Terry, Oops, my bad. Once you make a mistake, it can be hard to see it. Yes, that cap should be on the cathode. :-)

Carl, send me an email address and I will send you the custom library with conponents tha Steve McVoy and I have created.

This is nothing short of exciting. I've never seen a 30" B/W CRT set in my life.

I've only seen one 27" B/W, and it was a Magnavox, and was weak, even with a brightner.

Every 27" I ever seen was flat as a pancake, as well as every 24" (all Maggies).

I think it has to have something to do with the size, painting a bigger canvas with the same sized brush and all plus higher 2nd anode voltage pushing it harder.

John, is that the set I sold you many years ago? I'm refering the low-end chassis model. The same guy I bought my set from, also had a Crosley set like you're showing. That set had a 1952 model Admiral 27" chassis in it. The original chassis had a burned up flyback in it, and was scrapped.:thumbsdn:

IIRC, Admiral used the magnetic focused 27" glass CRT's. RCA was famous for the 27" metal cone CRT. Magnavox used the electrostatic focused glass CRT's, to the mid-60's. The last one being the solid state B&W chassis. All were 90 degree deflection.

John, did you ever trace out the schematic for the RA119B1 or ever find any service information on it? Is it similar to any other DuMont you've come across? I still haven't attempted restoring either the RA119A or the RA119B1 that I still have in storage.

Also, does anyone have an idea of how many of these 30-inch sets still exist? You and I have the only RA119B1 sets that I know of, and you have the only Crosley I've heard of.

Well, wiscojim, if you are Dave Nash, the answer is yes. Never did find any documentation for the set, but recapped it anyway. Now that I am drawing a schematic for the Crosley, I probably should do the same for the 30" DuMont. When/if I do, I will get you a copy. I have heard of a handful of 30" DuMonts. Steve McVoys ETF website shows 8 in his database. Probably a few more out there, but not a lot more.

John! I'm Dave Nash, AKA known as dieseljeep on this forum and also A-K. My beloved Diesel Jeep Liberty is in Jeep heaven now. Rust in peace.

Well then Dave, I am kinda confused. Who is wiscojim?

wiscojim is the guy who didn't sell you RA119B1 he has--and dieseljeep is the guy who sold you the one he had. :)

I'm lost, lol.

It all makes sense to me, but then again I've met wiscojim.

Wiscojim is Jim Menning from Appleton Wisconsin.

John, I'm really looking forward to seeing the Crosley when I come tommorrow.
Looks exciting....
Bill Cahill
I think I should have kept the 24" tv....

Bill, we will have a fun day.

wiscojim and deseljeep, its all sorted. And nice to put a few more names with aliases.

Work progressing on drawing the schematic for the Crosley TV chassis.....

Thanks guys, for sorting it out in my absence. I don't come here every day, and forgot to subscribe to the thread to receive the email notifications of new posts.

Yes, John, if you do ever get around to documenting the B1, I sure would appreciate copies of anything you come up with.

Wiscojim (Jim Menning from Appleton, WI)

I know this is a Crosley thread but as far as the DuMont RS goes I remember seeing something like a service bulletin from DuMont regarding a CRT retrofit for the 30BP4. It was supposed to be a kit of parts to install a "new" square tube in place of the round tube, almost like they were saying the 30BP4 is a dud and we ain't making any more of them.

Anyone heard of such a thing? Are there any more 30BP4 based sets?

I've got a question. The weak point on these large 19 to 30" DuMont CRTs are them going to air past the metal to glass joints, right?

What's to stop you from masking off the joints and applying a clear silicone top seal to eliminate future leaks? Or, another compound?:smoke:

I have one of the DuMont RA-119As, BTW.

Cosmetically, it's superb. In fact, it's the best set in my collection in terms of origional condition. It belonged to a VP of Engineering of Sprague Capacitors in the 50's.

I have a 27RP4 in new condition with great emissions. I'm thinking of using that instead of the 30. Or, maybe the guts of a modern LCD or plasma tv screen for video, sort of an old/new hybrid.

Didn't mean to hijack the thread. I now return you to our regularly scheduled program...:smoke:

Yeah, I've heard of the 27" Retrofit. From what I've read, it comprised a new 27" CRT, a new mask, and no doubt some parts to cut back on the anode voltage to the CRT, etc.:smoke: