Howdy all,

Here's a couple photos of the DuMont Ardmore my grandparents bought new back around 1950. It's been one of my dreams to get it working again since I was about 15. I'm now 49. I think it's time I get to work, what'cha all think? :yes:

As an admirer (never owned one) of Dumont telesets, you have a great project.
There are some real experts on these.
Good Luck.

Most you come across, have the case with the doors. This one is an interesting change and must be rarer.

Great set.

Appears to be an RA-108 variant. I'll be working on one myself over the next couple months.....get your soldering iron ready :yes:

Where are you from?

Appears to be an RA-108 variant. I'll be working on one myself over the next couple months.....get your soldering iron ready :yes:

Where are you from?

I'm out in Farmington, New Mexico, up in the Four Corners Region near Utah, Colorado, and Arizona.

You'll be working on a RA-108? Excellent! Vintage televisions are pretty rare out here. In fact, vintage ANYTHING is rare. Pretty much everything "vintage" has to be imported! I've never seen another DuMont Teleset in person (except for maybe in a museum). Seems a lot of folks have high regard for them. I know my grandfather said DuMont was pretty near top of the line in it's day. They seem to be well regarded around these here parts (Meaning the forum)! Except for maybe the 19AP4 CRT!

First order of business is going to be a full recap. Looks like about 50 or better caps including electrolytics. Tuner has seized (it still turned when I was 15!), hardened grease is likely culprit from what I've read. It's going to be a learning experience for sure! As for the CRT, since I don't have any specialized testing equipment, some luck is going to play into it. I know the heater filament is good, but that's about it for now. I'm beginning to doubt that a bad CRT was the reason the set was retired, but a lot can happen in 50 more years. I've got my eye out for a spare CRT already.

New roll of solder and a new soldering iron tip are at the ready!

-Cary

Yep, sadly right now the set is in the garage. I brought both chassis in the house, and plan to get the rest of the set in the house and into the basement after the Christmas tree is disassembled and the living room crap can go back in the living room ;)

The way things are going around here, I'm going to have DuMonts coming out of my arse soon :D . Here's the thread where I got this one a month ago. It's going to my friend Al, it was his mother's childhood set :)

http://www.videokarma.org/showthread.php?t=260099

Most you come across, have the case with the doors. This one is an interesting change and must be rarer.

Great set.

Thanks! I don't have much to judge by, since other than photos, this is the only DuMont I can remember ever seeing. Looking at photos of different DuMont sets, though, it does seem the ones with doors are more prevalent. The cover of the "John F. Riders" service guide shows six models for 1950, and four of them have doors. Interesting that out here in the west, as dusty as it is, that my grandparents would buy one without doors. Although where they lived out in California it was all citrus orchards and vineyards "back in the day", so maybe dust wasn't as big a deal.

ALMOST looks like a Royal Sovereign...THOSE are VERY rare..

Yep, sadly right now the set is in the garage. I brought both chassis in the house, and plan to get the rest of the set in the house and into the basement after the Christmas tree is disassembled and the living room crap can go back in the living room ;)

The way things are going around here, I'm going to have DuMonts coming out of my arse soon :D . Here's the thread where I got this one a month ago. It's going to my friend Al, it was his mother's childhood set :)

http://www.videokarma.org/showthread.php?t=260099

Man, I'm gettin' jealous of all the vintage sets that seem to be piled up back east! DuMonts everywhere! We just got our Christmas stuff down yesterday, and put away today, so we've got to put all the furniture back where it goes, and then I'll have room to at least get the chassis over here (the set is stored in a building right across the yard) and start start working on cleaning up the tuner while waiting for parts to arrive.

ALMOST looks like a Royal Sovereign...THOSE are VERY rare..

Almost, but it's not nearly large enough to be that. :no:

Almost, but it's not nearly large enough to be that. :no:

I just looked at this:

http://www.earlytelevision.org/dumont_ra-119.html

And now I have TV envy. :jawdrop:

My friend has the same Dumont that you have except his might not have the metal grille over the speaker grille cloth.
I have the RA-110 and it too is the type without doors and the tuning dial is at the bottom not the top and it too is square

that RA-119 has 45 tubes total and draws over 5 amps when playing , that must be one nice picture , the biggest roundie and black and white set ever.
mike

I think this has come up before, but does anyone know if any of the 30" Crosley sets have survived?

I think this has come up before, but does anyone know if any of the 30" Crosley sets have survived?

I believe 1-2 are known to exist, and I believe there is a restoration thread here on one of them...

I think this has come up before, but does anyone know if any of the 30" Crosley sets have survived?

I know of a collector in St. Louis who has one. He is a member here but doesn't visit much.

I'm having to crawl with the capacitor replacements on my RA-113 with the rectangular screen. BUT, every time I replace a few, I've noticed changes on the screen, and the sound.

I love all the room there is under the chassis on a DuMont.

I'm having to crawl with the capacitor replacements on my RA-113 with the rectangular screen. BUT, every time I replace a few, I've noticed changes on the screen, and the sound.

I love all the room there is under the chassis on a DuMont.

Happy to hear it's going well for you. That bolsters my confidence! The replacements for my missing tubes are starting to arrive. Got my capacitor order in today with "Just Radios", including the three 470pf 15kv caps that seem to be only available from him. I kicked around using high voltage ceramics, but figured ordering all my caps at once from Just Radios was a pretty good deal, including getting the HV caps that are guaranteed to work well. Also ordered the micas for the Horizontal output circuit, since it seems they are troublesome.

I was just joking with my wife that even if it turns out my picture tube is toast we should end up with a big ole' decent FM monaural radio! :lmao:

Ordered my caps from JustRadios in Canada. I know they get pretty good reviews, but I'm not sure about dealing with Canada Mail. Just found out if I want a tracking number, it costs an extra $10, so after dealing with JustRadio's Microsoft EXCEL ordering system yesterday for quite a while yesterday before I got a file they could read, I just found out they pulled my order from shipping today waiting to see if I wanted to pay the extra $10 or not. I guess I got spoiled by Antique Electronic Supply's ordering system, which is pretty easy to deal with, and of course, tracking is free. Man, I REALLY wish we still had a LOCAL electronic supply store!

I've ordered from Just Radios a few times and it's always been no problem. The problem with shipping doesn't really seem to lie with Canada Post but rather the US Customs service. Which is why the delay. Or so I've been told.

John Folsom has a restored 30" Crosley.

I've ordered from Just Radios a few times and it's always been no problem. The problem with shipping doesn't really seem to lie with Canada Post but rather the US Customs service. Which is why the delay. Or so I've been told.

Good to hear. I haven't ordered anything out of Canada in recent memory. I usually skip Canadian EBAY auctions because shipping is so high.

I agree many problems seem to be on the United States side. I have a tube for a 1945 Minerva radio floating around out there somewhere. Shipped before Christmas from Pennsylvania, and last tracked leaving Lehigh Valley, PA Dec. 26th..and it disappeared from radar after that.

A tube for my DuMont project wasn't shipped until the 27th out of Wisconsin, and I got it yesterday.

Most of the problems we've had with mail lately were because of our local carrier, and a tracking number is nice, because it keeps them on their toes, particularly when they mark an item as "delivered", and it's not in my mailbox!

Still waiting for my capacitors to show up in the mail, but we've got the DuMont in the house and I noticed the speaker is going to need a "re-cone". I've never done that before. I've done a little searching on the internet and found companies that will do the recone, and that's definitely an option, but does anyone know of a good supplier for a recone kit or parts to do it? It's a Jensen P10 speaker.

Found some added info: The SAMS says a Quam 10A4A speaker is a factory speaker as well. I wouldn't be opposed to replacing the whole speaker if I knew a good equivalent substitute.

Thanks!

Does the speaker really need reconing, or does it just have a few holes or rips?

I have successfully patched speakers using tea bag paper and flexible glue. You can buy a special "service cement" made by GC but many people report success using flexible glue from a craft store. Some people even use coffee filter paper. Your TV's audio section is not a high-fidelity system; a patched speaker will sound just like the original.

Tea bag paper is so light that it will blend in pretty well with the speaker material. If that doesn't satisfy you, you could darken it with a magic marker but I would not paint the cone.

Just an idea . . .

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

People lament the demise of local parts stores for small electronic parts, but I gotta tell you in general the local stores charged multiple times higher for the same capacitors and resistors you can get mail order, or internet order. We still have ONE local parts store that inventories capacitors and resistors (not Radio Shack), and their prices are high enough that I use them for emergencies only. And, they are a wholesale store.

Does the speaker really need reconing, or does it just have a few holes or rips?

I have successfully patched speakers using tea bag paper and flexible glue. You can buy a special "service cement" made by GC but many people report success using flexible glue from a craft store. Some people even use coffee filter paper. Your TV's audio section is not a high-fidelity system; a patched speaker will sound just like the original.

Tea bag paper is so light that it will blend in pretty well with the speaker material. If that doesn't satisfy you, you could darken it with a magic marker but I would not paint the cone.

Just an idea . . .

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

Howdy Phil!

Thanks for the idea on fixing the cone. I might be able to give the repairs a try, but I have a feeling it's toast. It's pretty crumbly. I noticed the speaker cloth on the front of the set bulging slightly and it's because there's chunks of speaker cone or foam resting in the bottom of the cone, against the cloth. Pressing lightly against he cloth, it's pretty "crunchy" sounding, and there are at least three places where the cone is cracked through right now. I'll have to pull the speaker to take a closer look. I might be able to get enough of a repair done that it will put out some kind of sound at least, when I get to that stage in the operation. There is certainly no hurry on the speaker, just want to line up a repair or replacement ahead of time while I'm stalled waiting for parts.

Thanks again!

If there is a foam ring that is supposed to bind the outer edge of the cone to the frame then I believe there are re-foam kits available.

EDIT: If it is truly toast measure the resistance of the voice coil and buy a speaker that has the same mounting dimensions and voice coil resistance if it is a PM type...If it is a field coil type then it gets more complicated.

Different sizes of new cones are cheap. Cut away the old cone leaving about an inch of old cone still attached around circumference of the voice coil, glue in the new one. The ones sold below have foam surrounds which might cause a problem with "bottoming" of the voice coil on loud bass so it might be necessary to devise a way to stiffen the surround a bit.

http://www.electronix.com/advanced_search_result.php?keywords=speaker+cone&x=0&y=0

Howdy!

Thanks for all the great advice! Especially the stuff about the speaker. The supplier for the replacement cones is great!

Finally started working on the set in earnest. Here's a photo of the cabinet after the cleaning with GOJO, and treatment with Howards "Mahogany" finish restorer and several applications of Howards "Feed n' Wax". I didn't want to do a complete strip and refinish, but it looked pretty ugly and "dried out" before, so I didn't know what I was going to be able to "get away with". Turned out pretty presentable, I think, without losing it's "oldie" charm.

Interesting to me was finding my grandparent's telephone number from the 1950's, starting with the "TR" exchange, written on the cover to the HV section. (As in "TRinity5-2437") Put there to ID the set while in the repair shop, my guess. I remember when I was little my grandmother was on a party line, and the only reason she got a "private" line was because, over the years, everyone else on the party line got private numbers! She was the only one still on the party line for years, getting the cheaper rate, until sometime in the late 1970's the phone company discontinued party lines and started charging her for a private line.

I was worried that the tuner might have a stripped/broken gear, since the knob would turn about a third each way and then bind. I knew to never force it, but we've had kids in the house over the last 20 years, and THEY didn't always know not to force it. Good news was the only reason it was binding was because the string had broken and was stuck in the gear teeth in a couple spots, causing the bind. I'd read about the dreaded "fiber gear", but it looks like the gears in my tuner are all metal.

Everyone around here who's looked at the underside of the chassis has found it pretty intimidating. The biggest recap I've done is on an RCA 99K console radio (1938), and it turned out good. This appears to be about twice that, so if I think of it that way, it's not so scary looking!

Mystery Tube! That black metal tube center-left in first photo has all the numbers rubbed off..and the photos in the SAMS showed a small glass tube in that spot..6AH6 video amp tube.

Glad I got the "Production Changes Bulletin" with the old SAMS folder..it shows that tube was changed to a 6AC7 tube on chassis code "R" and later. If anyone needs the production changes bulletin, let me know and I can scan it and sent it to you.

There was a tube in the tuner that I thought was wrong too, and was ready to order the one shown on the parts list, then got to looking at the changes bulletin and saw that the "mixer tube", 6AK5 on the parts list, was changed TWICE during later production runs...first to a 6BC5, and then to a 6BC6...and the 6BC6 is what was in that spot. That's when I figured out that the letters stamped on the back of the chassis are "chassis codes" that coincide with production runs shown on the changes bulletin. Mine is stamped "AM", which coincides with the last change on the list. Seems to denote that my set is from the last production run, and has every single change made..now I'm going to have to look over my capacitor list and see if I ordered any wrong due to production changes! Live and learn!

Second photo is of tuner string squirrel's nest after I "unclogged" it from the gears..looking close, the middle gear on the shaft MIGHT be fiber! Glad it didn't get chewed up!

Cary,
I'm truly awed at this project, to be restoring such a rare heirloom handed down within one's own family.
Wonder how many here are old enuff to remember the dreaded fiber timing gear in the Model A Ford engine.:D

Mystery Tube! That black metal tube center-left in first photo has all the numbers rubbed off..

You can usually find the tube number embossed in the metal part that surrounds the octal plug part of the tube.

You can usually find the tube number embossed in the metal part that surrounds the octal plug part of the tube.

Thanks. I took a look but don't see any number there. It's a JAN military surplus tube, apparently Ken-Rad..Ken is visible, "Rad" is worn off. The only numbers on it are a "V4", and "SC961A", but I haven't found any cross-reference to that number. There is also a barely visible "2" like it's the end of the a number, and cross reference to a 6AC7 is an 1852, so that's a possibility. Visually, it does appear to be the correct 6AC7, and the heater pinouts match, so I'm going to figure that's what it is for now since I don't have any reason to think someone would have put the wrong one there. It's the only metal tube in the TV, and apparently the 6AC7 is only available as a metal tube. I've now seen photos of the embossed number like you mentioned, and this tube definitely doesn't have one.

Recapping has begun! No turning back now....

apparently the 6AC7 is only available as a metal tube

A vanishingly rare 6AC7GT was produced. There is at least one vendor selling them for a very reasonable price; it's tempting to get one or two for experimentation to see if they are at all suitable for use in TVs.

Your set must be an early version. My RA-113 has a 7 pin miniature tube in that spot.

I've got a couple of used 6AC7 GT's here, according to my lists. Don't know if they are good or not.

Your set must be an early version. My RA-113 has a 7 pin miniature tube in that spot.

I've got a couple of used 6AC7 GT's here, according to my lists. Don't know if they are good or not.


According to the SAMS Photofact, production changed bulletin, your set might be earlier than mine. SAMS says: "To accommodate tube availability the video amplifier tube, V9 was changed to a type 6AC7. The tube socket wiring was changed when the 6AC7 tube was used." (I'm no expert, but that last sentence seems kind of obvious...since the tube it replaced was a mini glass tube and the "new" replacement uses an octal base.)

The bulletin doesn't give dates, but serial numbers and some chassis codes. Apparently this change was made on the 112A at #1232254.

The bulletin also seems to indicate that the change was only made on the RA-112A. There's nothing in the SAMS production changes bulletin that says it was ever changed in the RA-113. Don't know why they'd change it "to accommodate tube availability", and not change it across the board.

Thanks. I took a look but don't see any number there. It's a JAN military surplus tube, apparently Ken-Rad..Ken is visible, "Rad" is worn off. The only numbers on it are a "V4", and "SC961A", but I haven't found any cross-reference to that number. There is also a barely visible "2" like it's the end of the a number, and cross reference to a 6AC7 is an 1852, so that's a possibility. Visually, it does appear to be the correct 6AC7, and the heater pinouts match, so I'm going to figure that's what it is for now since I don't have any reason to think someone would have put the wrong one there. It's the only metal tube in the TV, and apparently the 6AC7 is only available as a metal tube. I've now seen photos of the embossed number like you mentioned, and this tube definitely doesn't have one.

Military tube then the number missing is VT-112


Chuck

Military tube then the number missing is VT-112


Chuck

a-HA! Thank you!

Yesterday was a marathon recap day! I'm not a very fast solderer, I have big hands, a 30 watt iron, and can't friggin' see close up through my glasses anymore (I'm resisting bifocals). And some of those caps are in VERY tight spots, particularly the two that were in the metal box in one corner of the chassis..it took forever to finagle those out and then in again.

I still have the HV section to tackle today, but I feel I'm on the downhill side!

Here's a couple noteworthy events:

The parts list in the SAMS photofact appear fairly accurate. In general, in replacing the paper caps, I ordered one or two spares of each, in case I screwed up and ruined some, and that's about what I ended up with. EXCEPT the .05 value. I ordered 11 of them, and I'm pretty sure I ordered at least two spares and maybe three, because it uses far more of them than anything else..and I only have ONE spare left.

I will say this: I didn't take into account the productions changes bulletin when I ordered caps, primarily because I didn't think of it until after the order was placed, so that could account for coming up "short"...glad I ordered extras!

There are a couple other values that I have extra leftovers of, and that might coincide with the "shortage" of .05's.

MOST notable is that I came up one short on 10uf 25 volt electrolytics. There is only one listed on the parts list (I didn't order any spare electrolytics, primarily because of expense, and not being familiar enough to know what I might use in the future, and I might lose them down the road anyway...you should see my shed..I figured they're a tad more durable with their aluminum housings, too) Turned out there's one in the "main chassis", and there there's another one "hidden" inside the aforementioned metal box in one corner of the chassis. The SAMS photofacts photos show it there, with the cover off the box, but there is nothing at all denoting it's existence. None of the usual arrows corresponding to SAMS location numbers point to it. Seems it was missed somehow. I didn't find it in the production changes bulletin either. Luckily it's a value that our local Radio Shack appears to stock, for a couple bucks, so I'll go get one today and get it in there.

Evidence of prior replacement caps: In one case, location C2 on the SAMS, calls for a 50uf 150 volt electrolytic. What was actually there was a 16uf 150. It's listed as a "filter". Don't know the result of such a change, but it's back to the value as listed in SAMS. I'm sure it was an early replacement, as it was soldered to a cut "pigtail".

There was also a couple older plastic caps in there. A HUGE Mallory .5 "Plascap" and a plastic Sprague.

Pretty much every old paper wax coated caps was "gooey". I saw in a previous write up by someone that they had to get the residue off their hands with Boraxo. I keep Boraxo around too! Works wonders!

I did not "restuff" any of the old cardboard or aluminum caps, but did leave them in place for aesthetics. Frankly, I'm not completely confident in my abilities, I've never worked with multiple can caps before, and figured if something goes haywire in the power up, I wanted to be able to see, smell, and hear what was going on...and having everything out in the open will make replacement in that case easier.

Here's a photo of what appears to me to be a couple of obvious failures:

Been my experience that some of the worst looking caps still work. You just never know.

You didn't leave the old caps in circuit, did you?

Been my experience that some of the worst looking caps still work. You just never know.

You didn't leave the old caps in circuit, did you?

No. I cut them out and replaced them all, except for the one electrolytic I came up short on..I soldered it back in as a "placeholder" until I can get a new one today.

I did leave the aluminum cans in place, so I assume their "grounds" are still attached to the chassis. (Except for one that is attached to an insulating board which seems to have a separate ground as part of another circuit, C6 in the SAMS: Decoupling and Vert. Amp. Cathode, so it's ground is still connected to it's circuit) But the positive leads were cut loose and soldered to the positive leads of the new electrolytics.

Would there by any problems associated with that? Should I "gut" the old aluminum can caps?

The appearance of an old capacitor tells you basically nothing unless it has catastrophically exploded.

Caps may look perfect on the outside and be utterly worthless on the inside. Conversey, as ggregg noted, an old cap can also look awful on the outside -- all grungy, dripping, etc. -- and still be operational.

It's like finding a 60-year old car in the barn and trying to guess the condition of its engine by inspecting its paint job. Not a reliable guide :)

The failure rate for 60-year old electrolytic and paper capacitors is so high that you will save a lot of time and grief if you simply replace them all.

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

The appearance of an old capacitor tells you basically nothing unless it has catastrophically exploded.

Caps may look perfect on the outside and be utterly worthless on the inside. Conversey, as ggregg noted, an old cap can also look awful on the outside -- all grungy, dripping, etc. -- and still be operational.

It's like finding a 60-year old car in the barn and trying to guess the condition of its engine by inspecting its paint job. Not a reliable guide :)

The failure rate for 60-year old electrolytic and paper capacitors is so high that you will save a lot of time and grief if you simply replace them all.

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

Howdy Phil!

So a cap with both ends bulged out can still be, technically, "good"?

Guess I should save those for spares! :lmao:

Photo of finished recap..except for the one electrolytic next to the transformer center-left, which is the one I came up short on because the SAMS parts list only indicates one 10uf 25 volt cap used. That one will be replaced later today, "Radio Shack be willing and the creeks don't rise". The other one is upper far right, normally covered by a metal box. It's tucked in behind the upper end of the yellow replacement cap up there. I put the one I had up there because it looked tough to get to, and it was, without a doubt, the most frustrating cap to install on the entire set so far.

If some of the electrolytic replacement looks a bit "ham-fisted", well, "c'est la vie", once the chassis is back in the set, I won't be able to see 'em, even from my house!

Lookin' good. I used to could see up close at a microscopic level back in my 20's, now I need to rely on a couple different strengths of reading glasses that I pick up at the grocery store.

Lookin' good. I used to could see up close at a microscopic level back in my 20's, now I need to rely on a couple different strengths of reading glasses that I pick up at the grocery store.

Thanks! It's not as tidy as if I'd restuffed the cans and cardboard tubes, but there's a lot of room under that chassis for a lot of stuff.

I've been wearing specs since I was about 10 or earlier, but I used to be able to focus close up still wearing them. Over the last few years, that ability has just about disappeared. I've always been heavily "near sighted". Now, with my glasses on, I can see clearly from about a foot away to out as far out as I want, but things get blurry close up. I take my glasses off, and I can see crystal clear from about two inches out to about 6 inches out. There's an area between the 6 inch and one foot mark where I can't see ANYTHING clearly, with or without glasses, and that's where bifocals would come in.. call it vanity, but I'm resisting "old people glasses" as long as I possibly can! :cool:

Heh, I hear that. When I finally assented to trifocals I went home from the examination and found a letter in the mail from AARP.

fml :dunno:

Thanks! It's not as tidy as if I'd restuffed the cans and cardboard tubes, but there's a lot of room under that chassis for a lot of stuff.

I've been wearing specs since I was about 10 or earlier, but I used to be able to focus close up still wearing them. Over the last few years, that ability has just about disappeared. I've always been heavily "near sighted". Now, with my glasses on, I can see clearly from about a foot away to out as far out as I want, but things get blurry close up. I take my glasses off, and I can see crystal clear from about two inches out to about 6 inches out. There's an area between the 6 inch and one foot mark where I can't see ANYTHING clearly, with or without glasses, and that's where bifocals would come in.. call it vanity, but I'm resisting "old people glasses" as long as I possibly can! :cool:

I went with blended tri-focals.
I had the old style lined bi-focals, as safety glasses, years ago. They were nasty for night driving. It's bad enough, that you have to wear glasses. You might as well get glasses you don't mind wearing. :yes:

Finished up the recap job this eve, replacing the three 10000 volt caps in the HV section.

Reassembled, and powered up..no fire...no smoke..no buzz...no tubes glowing..no nothing....

Totally dead.

Did a bit of tracing of the power circuit through the on/off switch..and wouldn't it be a bummer if the set has been dead since around 1960 due to a bad power switch?

Well..the power switch IS bad. I jumped it and everything lit up on the bench. Still no explosions, no fire, no smoke, etc. But every tube lit up as it should.

Anyone have any luck repairing a power switch? If not, any idea where to get replacements? The switch is a combination on/off switch-volume control and hold control. I can solder in a temporary toggle switch for testing purposes.

I've posted a "Want Ad" with part numbers in the "Classifieds" section.

Finished up the recap job this eve, replacing the three 10000 volt caps in the HV section.

Reassembled, and powered up..no fire...no smoke..no buzz...no tubes glowing..no nothing....

Totally dead.

Did a bit of tracing of the power circuit through the on/off switch..and wouldn't it be a bummer if the set has been dead since around 1960 due to a bad power switch?

Well..the power switch IS bad. I jumped it and everything lit up on the bench. Still no explosions, no fire, no smoke, etc. But every tube lit up as it should.

Anyone have any luck repairing a power switch? If not, any idea where to get replacements? The switch is a combination on/off switch-volume control and hold control. I can solder in a temporary toggle switch for testing purposes.

I've posted a "Want Ad" with part numbers in the "Classifieds" section.
First, you have to determine what make of control it is. CTS, seems to be the most common. It could be Mallory, Clarostat, IRC or another East coast manufacturer.
Then, take the control all apart and transplant a known good switch.
One of the posters on this forum, could make up a control. IIRC, you sent them the defective control and they would repair or duplicate it. :thmbsp:

First, you have to determine what make of control it is. CTS, seems to be the most common. It could be Mallory, Clarostat, IRC or another East coast manufacturer.
Then, take the control all apart and transplant a known good switch.
One of the posters on this forum, could make up a control. IIRC, you sent them the defective control and they would repair or duplicate it. :thmbsp:

The one that is in there is marked "Centralab". I don't have any spares of any kind, so I'm going to have to locate a complete replacement. I would guess that an IRC switch won't fit on a Centralab control?

The one that is in there is marked "Centralab". I don't have any spares of any kind, so I'm going to have to locate a complete replacement. I would guess that an IRC switch won't fit on a Centralab control?

How could I forget "Centralab". They were on the Northeast side of Milwaukee.
I don't even think a CRL replacement switch would work. OEM and replacement parts, even from the same manufacturer, didn't interchange.
I'm only going by memory, as it's been ages. :sigh:

How could I forget "Centralab". They were on the Northeast side of Milwaukee.
I don't even think a CRL replacement switch would work. OEM and replacement parts, even from the same manufacturer, didn't interchange.
I'm only going by memory, as it's been ages. :sigh:

The SAMS photofact lists a "Concentrikit" by IRC, and lists a bunch of individual part numbers for individual components of the switch. Amazing how folks used to be able to repair stuff on that level!

I might try taking the switch apart and seeing if I can shoot some contact cleaner in there. It still "clicks" as if it's turning one and off...but apparently no internal contact. Don't have anything to lose since it doesn't work now.

I've found switches where the contacts are stuck open simply from setting too long and hardened grease. Sometimes a squirt of tuner cleaner/lube into the switch and cycling several times will free things up. One the other hand the contacts may be badly burned, in which case you'll need a replacement switch.

Edit - just seen you're already on the right track in you last post.

O.K., no luck trying to get the on/off switch to work, so I soldered in a jumper and am working the set off a switched power strip.

I remember saying early on that if I didn't get a TV out of this DuMont, at least I'd have a heck of a big old mono FM radio...and that's what I've got so far! :music:

I'm wondering though, since I've never seen this set do anything (including play FM radio, so I have made progress), exactly how is it supposed to act?

It has a three-position switch which switches from FM to TELEVISION to PHONO.

I'm getting FM radio on both the FM and TELEVISION settings, and when I switch to PHONO, the sound kicks off. On PHONO, I can plug in a phono cord and get a buzz if I touch the center conductor on the other end of the phono cord, so that seems to be working (I must have SOMETHING around here I can plug into that jack! Man, has technology changed! Curse you Optical Audio and HDMI!). On all settings, the heater filament in the picture tube glows. At no time, on any setting, does it sound like the picture tube is firing up..no static electricity sound, etc. No noise from the HV section.

I get a VERY dim eye tube, barely see it, but there is some action there while tuning through FM if I look close enough. Could be a wore out eye tube.

It appears I have a balky FOCUS control. When I turn that control, there is a "dead" spot in the middle where the sound drops out, but it picks up at either end, far left or far right. What the FOCUS has to do with that I have no idea at present.

My first though is that the FM/TELEVISION/PHONO switch isn't working correctly. Should I be getting FM sound on either TV or FM settings? Should the picture tube heater be lit at all times, on all settings? I would assume that switching to FM, the picture tube should shut off, but is that handled through the HV section alone?

Thank you for any thoughts/advice.

Cary, I believe you said this is your first TV, correct?

I also understand that you have neither substitute tubes, nor a tube checker, correct?

Next step is to dim your lights and verify that the plates on the 5U4 rectifier, the 6BG6 Horizontal Output, and the 6W4 Damper are not getting pink as this indicates something is badly wrong.

If any plates are glowing, turn the set off immediately.

Since you have not replaced any resistors, I assume that a resistance check will not be productive at the moment.

I cannot call the Sam's part numbers as the only schematic of the RA-112 is the Riders one at ETF which uses the factory numbers.

http://www.earlytelevision.org/tv_schematic_diagrams.html

However, I'm going to suggest that you measure all the resistance reading listed in Sam's from tube sockets, with the set unplugged. This will give practice for the next step and it might spot a pre-existing problem.

Make a Xerox of the two pages of Sam's and write down the resistance, at each point and color marking the ones that are off by more than 20%.

If no tube plates were getting too hot, your next step is to check the voltages that are shown in Sam's voltage chart.

Follow the same procedure of writing them down, again marking those 20% off in a different color.

James

Yes, you will get FM reception in both FM and TV positions and the CRT filament is lit at all times.
The only thing that happens in FM mode is that the CRT brightness is cut off. All the TV circuits are still running including the high voltage.
So you really are wearing out the TV tubes and CRT while just listening to the radio.

It appears I have a balky FOCUS control. When I turn that control, there is a "dead" spot in the middle where the sound drops out, but it picks up at either end, far left or far right. What the FOCUS has to do with that I have no idea at present.


Check your schematic. Your B+ is fed through your wiper on the focus pot. I assume that is a wire wound. You might see if it is open in the center as that could be causing part of your problems.

. . . . . (I must have SOMETHING around here I can plug into that jack! Man, has technology changed! Curse you Optical Audio and HDMI!).

I would be cautious about plugging in anything that uses transistors or chips into the record player jack, because this set has a semi-hot chassis though a 100 K resistor. Not enough to current there to hurt a person, but it might be terminal to a transistor circuit that was not buffered against a little AC.

James

Yes, you will get FM reception in both FM and TV positions and the CRT filament is lit at all times.
The only thing that happens in FM mode is that the CRT brightness is cut off. All the TV circuits are still running including the high voltage.
So you really are wearing out the TV tubes and CRT while just listening to the radio.
I have a 15" RA103 or 104. It has the regular Dumont chassis, with the inputuner and FM radio. It also has a record changer and a AM radio chassis.
The strange part is the phono audio goes through the TV chassis. The radio is only used for AM radio reception. It's a six tube job, with a tuned RF stage.
Both chassis have a SE 6V6, output stage. The selector switch on the radio, cuts off the power to the TV chassis and switches the speaker to the radio chassis, when it's being used for AM reception.
I, personally, would have used the radio chassis for record reproduction.

Hey guys! Lookee what I found!

:thmbsp: :rockon: :yippy: :beer:

Cary, I believe you said this is your first TV, correct?

I also understand that you have neither substitute tubes, nor a tube checker, correct?

Next step is to dim your lights and verify that the plates on the 5U4 rectifier, the 6BG6 Horizontal Output, and the 6W4 Damper are not getting pink as this indicates something is badly wrong.

If any plates are glowing, turn the set off immediately.

Since you have not replaced any resistors, I assume that a resistance check will not be productive at the moment.

I cannot call the Sam's part numbers as the only schematic of the RA-112 is the Riders one at ETF which uses the factory numbers.

http://www.earlytelevision.org/tv_schematic_diagrams.html

However, I'm going to suggest that you measure all the resistance reading listed in Sam's from tube sockets, with the set unplugged. This will give practice for the next step and it might spot a pre-existing problem.

Make a Xerox of the two pages of Sam's and write down the resistance, at each point and color marking the ones that are off by more than 20%.

If no tube plates were getting too hot, your next step is to check the voltages that are shown in Sam's voltage chart.

Follow the same procedure of writing them down, again marking those 20% off in a different color.

James

Howdy James!

Yes, this is my first set. I've done a couple tube radios, and a wind up phono (completely different tech!) The reason I've got this DuMont is because it's a family heirloom. I've run into some pretty good luck with it so far.It's nice to know it's history, and it's been in my possession for over 25 years, and I've been pretty protective of it.

As it started getting darker outside, I was able to look at the tubes as you suggested. No pink plates, so that was good. The darkness is also what led me to noticing that the CRT was apparently "coming back to life". I could see some VERY faint flickering, and started moving the ion trap around, and was able to brighten up the CRT immensely. I was pretty encouraged by that. Now I just have to figure out how to introduce a a signal so I have something to actually see.

We actually still have at least one UHF analog station broadcasting here..but alas, this DuMont has no UHF!

Thank you for the "system" for checking the resistors. I figure There's going to be some that need replacing. There's a LOT of them in there!

I do not have a tube checker. I've met a couple people who say they have one "somewhere", and say I can use it when they find it, but no one has dug one up yet. I'm starting to get enough tube driven stuff around here that buying a checker might be worthwhile. I do have a few extra tubes now. TV tubes are remarkably cheap, so buying them in lots is almost as cheap as buying one. I've got a couple 6J6's, 6BA6's, and several spare 6AU6's.

Yes, you will get FM reception in both FM and TV positions and the CRT filament is lit at all times.
The only thing that happens in FM mode is that the CRT brightness is cut off. All the TV circuits are still running including the high voltage.
So you really are wearing out the TV tubes and CRT while just listening to the radio.

Thanks! Now I understand how it works, and now that the CRT is lit up, I see it's working just as you describe.

Now I'm no engineer, but "I am a thinker"..and it sure seems DuMont could have come up with a better setup than to have to power the entire TV, and wear out ALL the tubes (including CRT!) just to listen to the radio!

I've read of folks putting a circuit into their old radios with "eye tubes" that shuts off the eye tube a few seconds after tuning stops. I guess certain German radios did this right from the factory. With radio "eye tubes" getting scarce and expensive, I've thought about it for my '38 RCA console. I've read that useful life of a radio "eye tube", 6U5, 6E5, and the like, is around 1000 hours. Not very long if you listen to the radio a lot!

Just dreaming out loud here (figuratively speaking..errr...typing), but I wonder how hard it would be to unobtrusively install some sort of cutoff that kills the TV circuit..particularly CRT, when listening to the radio. TV tubes, in general, are plentiful and cheap..but CRT's sure aint!

It's always exciting to see that first light on the screen.

You may be close to having a coherent picture. What are you using as a source -- VHS player, DVD player, etc.?

As you may know, wherever your TV has two tubes of the same type (say, two 6AU6), you can swap them and see what happens. If no change, then chances are that they're either both bad or both good. In restoring dozens of radios and TVs, I've found that the majority of old tubes found in those sets were still good, so the odds are somewhat in your favor.

You can also perform a simple dud/not-dud test on a tube's filament with an ohmmeter as described at http://antiqueradio.org/FirstStepsInRestoration.htm .

I would not go nuts replacing marginal resistors at this stage. If one is WAY off or totally failed, then replace it, but consider that many parts of your TV are working "purty good" if you're seeing a lit screen. Going overboard with mass replacements creates more opportunities for mistakes. As earlyfilm noted, it's worthwhile to do the systematic tests and record the results in any case.

At this stage, I would focus on getting an image on the screen along with audio. Then you can do selective troubleshooting.

Good progress so far!

Phil Nelson

It's always exciting to see that first light on the screen.

You may be close to having a coherent picture. What are you using as a source -- VHS player, DVD player, etc.?

As you may know, wherever your TV has two tubes of the same type (say, two 6AU6), you can swap them and see what happens. If no change, then chances are that they're either both bad or both good. In restoring dozens of radios and TVs, I've found that the majority of old tubes found in those sets were still good, so the odds are somewhat in your favor.

You can also perform a simple dud/not-dud test on a tube's filament with an ohmmeter as described at http://antiqueradio.org/FirstStepsInRestoration.htm .

I would not go nuts replacing marginal resistors at this stage. If one is WAY off or totally failed, then replace it, but consider that many parts of your TV are working "purty good" if you're seeing a lit screen. Going overboard with mass replacements creates more opportunities for mistakes. As earlyfilm noted, it's worthwhile to do the systematic tests and record the results in any case.

At this stage, I would focus on getting an image on the screen along with audio. Then you can do selective troubleshooting.

Good progress so far!

Phil Nelson

Howdy Phil!

Thank you for the words of encouragement! My one big, huge, overwhelming "if" was the CRT. I had no idea what it was going to do. Family legend said it was a "bad picture tube" that retired the set, but after I learned something about how vintage TV's work, the symptoms didn't fit. I had hope that something else was bad..now it's looking like it was a bad power switch all along. Still, the only positive test I could perform was your suggestion of checking the filament, and it did test good.

I'm not sure what to use for signal source.."earlyfilm" mentioned a slight voltage travels through the chassis on this set that could travel the lead and damage a transistor device...might it damage a VCR or DVD player?

Any suggestions?

If your VHS or DVD player has an output in the back marked "To TV" or "RF," you can connect that to the TV's antenna terminal through a coaxial cable.

If the player has A/V output (1 video plus 2 audio for stereo), then you can connect those to an RF modulator like this:

http://www.radioshack.com/product/index.jsp?productId=2103095#tabsetBasic

You would then connect the RF modulator's output to the TV's antenna terminals, again using a coaxial cable.

This is how TV collectors watch recorded material on their TVs nowadays, since the USA discontinued analog TV broadcasts several years ago.

You can buy that kind of RF modulator other places; I only gave a Radio Shack link because their stores are found in many cities.

Earlyfilm was talking about a different connector on the TV -- the phonograph input jack. That was designed to use an old-school input. Modern solid-state devices (iPod, you name it) are not designed for that use and might be damaged if you plug them in directly.

It's possible your CRT is weak, but in the photo it is lighting up enough to see, so it should work well enough to get you through the restoration, at least. Perhaps when you're done it will be good enough to watch. The CRT used in these sets is not super-rare, so if you decide you need a better one, you should be able to find one eventually.

Phil Nelson

Cary,

First congratulations on getting one of the more complicated vintage TV sets, or I should say "systems," lighting up! These early Du Mont's are not what we call starter sets!

That set must have had years of dry storage storage! Usually one can hear the HV crackling up for the first time, but I forgot that you were from the driest area of the US.


I'm not sure what to use for signal source.."earlyfilm" mentioned a slight voltage travels through the chassis on this set that could travel the lead and damage a transistor device...might it damage a VCR or DVD player?


Sorry I confused you. I was talking about modern AUDIO devices. Many of these are not protected against for this issue. Anything that is supposed to go through an antenna or video feed should be OK. Also, older tube era phonographs should be OK.

I'd try a your cable box if you have cable and it has an RF (channel three or four) analog output. If not, find one of the used set top boxes used to convert digital over-the-air programs in the early days of digital, that will be better. The most common problem with both of these is their output is slightly stronger than old high performance fringe area sets like your DuMont is expecting and that may cause sound buzz or picture bending, or even the picture flipping to negative.

The first thing to remember about a tube checker is that it also has to be recapped and then possibly recalibrated, since the same parts in them age just as a TV does.

Also you need to try to see if the focus control is just dirty or if it has failed. You have pretty high voltage there, so after cleaning, be sure to let the control completely dry before powering up the set, or you could fry it. This control is center fed from the raw B+ and helps provide both the 300v and 200v sources.

James

The only thing that happens in FM mode is that the CRT brightness is cut off. All the TV circuits are still running including the high voltage.
.

Not so, not with a Du Mont anyway. Sets that did no more than blank the raster with an external phono input are really nothing more than a gimmick.


Any design that was done at all seriously will cut the voltage to the sweep section when in a non-TV mode and the Du Mont sets do this.

ETA: Well damn. I just checked the RA-113 skiz and can see there came a time when the Du Mont engineers stopped being serious! Even my '51 Emerson combo kills the sweeps in phono mode...and it ain't no Du Mont.... :no:

Yeah, I was quite surprised to discover that while restoring an RA-113. I have a GE-802 with a beefy switch that cuts juice to most of the set while not in TV mode.

Cary,
Congrads on the successful power up. There is one paper cap i'd heartily recommend replacing as the first order of business. That's the coupling cap going to the control grid (G1) of the HO tube. The slightest leakage in this cap will cause the tube to overconduct, shortening its longevity.
If the tube is 6BG6, G1 is pin 5.



OOPs! Senior moment.:o Looks like you've already done a recapping. Presumably you got that one already.

Hi Cary,

I just 'tuned in' to this thread. Congratulations on resurrecting the Dumont. Not an easy first project.

I have a soft spot for DuMonts, obviously...:smoke:

http://i268.photobucket.com/albums/jj7/300cSRT8_photos/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119AFinalAssembly2007_zps91b20d88.jpg (http://s268.photobucket.com/user/300cSRT8_photos/media/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119AFinalAssembly2007_zps91b20d88.jpg.html)

http://i268.photobucket.com/albums/jj7/300cSRT8_photos/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119A-BrightnessContrast3005_zpsa85c7422.jpg (http://s268.photobucket.com/user/300cSRT8_photos/media/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119A-BrightnessContrast3005_zpsa85c7422.jpg.html)

Turns out the rheostat that controls the focus is toast. About a third of the wire winds are eaten through.

I did hook up an old VCR/DVD combo with a built in RF output and was able to get a blurry picture..so that's good news.

Any hints on where I can find a 1200 OHM 25 watt ceramic rheostat with a long shaft? The Clarostat part number is RTV-220.

Photo soon...

Hi Cary,

I just 'tuned in' to this thread. Congratulations on resurrecting the Dumont. Not an easy first project.

I have a soft spot for DuMonts, obviously...:smoke:

http://i268.photobucket.com/albums/jj7/300cSRT8_photos/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119AFinalAssembly2007_zps91b20d88.jpg (http://s268.photobucket.com/user/300cSRT8_photos/media/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119AFinalAssembly2007_zps91b20d88.jpg.html)

http://i268.photobucket.com/albums/jj7/300cSRT8_photos/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119A-BrightnessContrast3005_zpsa85c7422.jpg (http://s268.photobucket.com/user/300cSRT8_photos/media/DuMont%20RA-119%20Royal%20Sovereign/DuMontRA-119A-BrightnessContrast3005_zpsa85c7422.jpg.html)

Nice stuff! I hope to get as good a picture out of mine eventually. I just determined my focus control rheostat is a goner..

The SAMS calls for a 1200 ohm 25 watt rheostat...

Surplus Sales has a 1000 ohm 25 watt, left side of the page on link below..for $8..would that be close enough?

http://www.surplussales.com/Potentiometers/Rheostats/PotsRheost-4.html

Turns out the rheostat that controls the focus is toast. About a third of the wire winds are eaten through.

I did hook up an old VCR/DVD combo with a built in RF output and was able to get a blurry picture..so that's good news.

Any hints on where I can find a 1200 OHM 25 watt ceramic rheostat with a long shaft? The Clarostat part number is RTV-220.

Photo soon...

Yup. Surplus Sales of Nebraska.

There's a 1k 25w and a 1.5k ?w on this page:

http://www.surplussales.com/Potentiometers/Rheostats/PotsRheost-4.html

Focus Controls are a soft spot on these old DuMonts.

Ooops. See you've already caught the SS of N page.

I bought a bunch of those a couple of years ago to keep in stock.

You can hang a 25ww resistor off the end of the 1k Control to gain a little more range, if need be.:smoke:

Surplus Sales has a 1000 ohm 25 watt, left side of the page on link below..for $8..would that be close enough?[/url]That's exactly what I installed in my RA-113.

http://antiqueradio.org/art/DuMontRA-113FocusPotNew.jpg

The shaft was too long, so I cut it down and filed a flat area to fit the knob.

Phil Nelson

Outstanding! Thanks for the input..I'll get a couple of those rheostats ordered so I have a spare around.

Restrung the tuner dial tonight. The list of "to-do's" gets shorter!

I called my mother a couple nights ago and told her "the DuMont lives!". She remembered when I hefted that sucker out of grandma's house and into her van, by myself, about 25 years ago. She used to watch that TV when she was a little girl. When she comes out to New Mexico for a visit later this year, it looks like she'll be able to watch it again. That's pretty cool.

I'll get a couple of those rheostats ordered so I have a spare around.

Cary, if it were me, I'd also purchase one of the $1.25 10 watt 200 ohm resistors that Nebr Surplus has and add it on to one end of the pot. Yes, I know the new pot is within 20% of the original, but that pot and the focus coil are in a divider network in your power supply. I suspect that with both the new pot and that resistor in place your B+ supply voltages will be better behaved, and this could possibly improve your weak reception.

Jas

Cary, if it were me, I'd also purchase one of the $1.25 10 watt 200 ohm resistors that Nebr Surplus has and add it on to one end of the pot. Yes, I know the new pot is within 20% of the original, but that pot and the focus coil are in a divider network in your power supply. I suspect that with both the new pot and that resistor in place your B+ supply voltages will be better behaved, and this could possibly improve your weak reception.

Jas

Thank you for the suggestion. I went ahead and ordered two rheostats and two resistors so I'd have a spare set. Does it matter which side of the pot I put the resistor on?

According to the tracking number, the package from Surplus Sales is on schedule to arrive tomorrow. I'm looking forward to install!

Does it matter which side of the pot I put the resistor on?

Whichever side puts the best focus nearest to the center of the pot.

With the non-open pot in the bleader circuit, it will shift some of the various "B" voltages and you may have to tweak some of the adjustments, including the ion trap.

J.

Whichever side puts the best focus nearest to the center of the pot.

With the non-open pot in the bleader circuit, it will shift some of the various "B" voltages and you may have to tweak some of the adjustments, including the ion trap.

J.

Well, I had a 50/50 chance of getting the extra 200 ohm resistor on the "right" side of the focus pot...and I got it wrong. Best focus is now with adjustment turned all the way to the left. Pulled chassis to move 200 ohm resistor to other side of pot.

I did get a MUCH better picture, though. Eye Tube still very dim. Think it's a bad tube, since I could see faint action looking directly at tube.

As far as the picture goes, a lot of "ghosting", and the top of the screen bends right..I think...I've been looking at the screen in a mirror as I make adjustments out back.

Gonna move resistor and try again. Don't think it's going to change picture quality much, if at all. l

As far as the Dumont tuning tube is concerned, you will notice that there is a resistor installed at the back of the socket. These are frequently bad, and need replacing.:smoke:

As far as the Dumont tuning tube is concerned, you will notice that there is a resistor installed at the back of the socket. These are frequently bad, and need replacing.:smoke:

Thanks!

Got the new focus control yesterday, and like Phil said earlier, the shaft is a tad longer, and needs the flat filed into it. A little work with the Dremel tool and it was ready to go.

These controls from Surplus Sales of Nebraska were packaged in 1960! Talk about NOS! I almost hated to open up something that was sealed in it's package when Dwight Eisenhower was President.

In the interim I had also cut new glass for the dial window to replace the broken one.

I've read references to both plastic and glass being used for the dial window. It looks like mine had some extra "fingers" soldered on to hold thicker glass than what was originally in it. Don't know the history of that modification, but apparently it was for standard 1/8 inch window glass, because that is what fit.

Does anyone know if the brass trim around the dial window is solid brass? It's not magnetic, so I think it is. There's a bit of pitting on the bottom near the tuner knob..probably from fingers touching it. I'm wondering how much polishing it can take. I don't want to polish brass plating off if that's all there is.

The resistor on the tuning eye is inside the base cover. On my set, the tube was bright, but had only minute movement on the display. The new resistor brought that back.

The tube is a 6AL7-GT. It's not terribly expensive.

The resistor on the tuning eye is inside the base cover. On my set, the tube was bright, but had only minute movement on the display. The new resistor brought that back.

The tube is a 6AL7-GT. It's not terribly expensive.

And the value of the resistor is often 1 meg ohm. Check it for color bands and since you are going to the trouble of checking it, might as well replace it with a new one?

The resistor on the tuning eye is inside the base cover. On my set, the tube was bright, but had only minute movement on the display. The new resistor brought that back.

The tube is a 6AL7-GT. It's not terribly expensive.

I've got another 6AL7-GT in the mail on the way to me..due Friday. You are absolutely correct about them being pretty cheap..shipping and all it was around $8. Much better than the eye tube for my 1938 RCA 99K! The 6U5 tube that radio uses are going for astronomical prices on Ebay..last one I bid on ended up going for over $30, but not to me.

Not sure what the deal is with my eye tube, but figure I can't really dig into it until I have one I know is good, or I could end up chasing a "problem" that doesn't exist. When I first turn the set on and it's warming up, the eye tube will light a little bit, not real bright but visible, then it fades out. It's never a real "crisp" looking display even when I can see it, and the tube display has a smeared "burned" look to it even when there's no power to it.

Spent this morning watching "Cahill, U.S. Marshall" on the DuMont, while working on adjustments to the set. I've got a big mirror sitting in front of it so I can see what affect the adjustments are having.

I want to thank everyone who has offered advice to this novice! I've been able to resurrect my grandparents old Teleset from a novelty/conversation piece/plant stand to an actual, working television!

It does seem the picture tube, while viewable, is not near "bright". I'm getting a full picture, have been able to center it in the CRT, and can get it pretty well focused. Unless there is some other factor that affects brightness, I'd say I am going to have to go on the hunt for another 19AP4. Not an easy task out here in New Mexico, where there are VERY few vintage televisions. I am VERY happy with what I have, though, considering the set has been "dead" for around half a century.

There are some very thin diagonal white lines that appear on the CRT from time to time, mostly they seem to be associated with the brightness and contrast settings. They cross the CRT from lower left to upper right. So skinny, I've not been able to photograph them. They do not distort anything on the screen. Any hints?

I've noticed that the "Brightness" control affects the focus quite a bit. Is this normal?

Lastly, when tuning, with the continuous tuner, I've noticed the picture seems to come in well, then seems to lose it's sync (get "wobbly"), then comes in good again before tuning out. I've attempted to sync the sound to the places where there is the best picture, but the sound seems to want to come in strongest closest to the "wobbly" picture. Any hints on what to check for?

Thanks!

your brightness focus issue and lines which are retrace lines and lack of brightness suggest a weak crt , if you are not planning on running it for hours on end and only an hour or so a day or every other day I would put a brightener on it , you will get better brightness , contrast and less of the lines and control the focus / brightness , if you had a crt tester you could see what it reads , my Dumont has a weak one so I put a brightener on it but added a resistor so its only 7 or so volts , this is enough to improve the picture and not push it that hard , at 7 volts emissions rise to good on mine, a regular brightener could be 8 or 9 volts , If you don't have one I might be able to space one.

as far as the wiggle it could be where you are at in tuning range , if you reduce the agc it may improve this as well and reduce the wobbly effect .

mike

Sounds like you are seeing what is called 'retrace lines'. The set is supposed to turn off the electron gun when it is in between scanning different scan lines or frames (via a 'blanking circuit'), but some sets don't have that circuitry (I can't see that being the case for a Dumont though), and others it is either insufficiently designed not working due to bad components.

BTW if you play a VHS tape or DVD that has macrovision copy protection on it then that will partially disrupt the blanking circuit and place a series of bright dashes on screen.

your brightness focus issue and lines which are retrace lines and lack of brightness suggest a weak crt , if you are not planning on running it for hours on end and only an hour or so a day or every other day I would put a brightener on it , you will get better brightness , contrast and less of the lines and control the focus / brightness , if you had a crt tester you could see what it reads , my Dumont has a weak one so I put a brightener on it but added a resistor so its only 7 or so volts , this is enough to improve the picture and not push it that hard , at 7 volts emissions rise to good on mine, a regular brightener could be 8 or 9 volts , If you don't have one I might be able to space one.

as far as the wiggle it could be where you are at in tuning range , if you reduce the agc it may improve this as well and reduce the wobbly effect .

mike

Thank you for the info!

I forgot to mention that the white lines are stationary, if that makes a difference. I still don't have access to a CRT tester/rejuvenator. Almost bought on on EBAY, but then thought I might only use it once on this set and never use it again...I don't know if I've caught the "TV bug" yet..if I have, it's going to have to continue on much smaller sets! If you don't have a spare brightener, if you could tell me what to look for, I see there are tons of them for sale on EBAY pretty inexpensively. My only concern would be blowing out the CRT I have left and then being back to nothing. But if they are pretty safe, it might be worth a shot. It's not like the CRT is going to get better all by itself..and it may be a long while, if ever, before there's anyplace to send it off for rebuild.

I was running the TV off a VCR/DVD combo with RF output..but I can't get the DVD side to work. So I was watching a VHS tape. I remember VHS wouldn't always put out the best picture even on modern color sets, particularly when they started playing around with copy protection.

My DuMont set has a "local/distance" switch on the back which I believe has to do with the "gain". I had it set to "local". When I switched it to "distance", the whole picture would start to roll.

Sounds like you are seeing what is called 'retrace lines'. The set is supposed to turn off the electron gun when it is in between scanning different scan lines or frames (via a 'blanking circuit'), but some sets don't have that circuitry (I can't see that being the case for a Dumont though), and others it is either insufficiently designed not working due to bad components.

BTW if you play a VHS tape or DVD that has macrovision copy protection on it then that will partially disrupt the blanking circuit and place a series of bright dashes on screen.

Thank you! I'll have to take a look at the schematic and see if I can identify the circuit you mention. I was watching a VHS tape, I'll have to take a look and see if it had macrovision. I remember it being a problem with some VCR/TV setups even back in the day when VHS was king. We had to constantly fiddle with the tracking trying to get rid of what looked like interference.

One thing that WAS an improvement today was that I switched around the three 6SN7GT tubes. One is vertical oscillator, one is vertical amp, and one is horizontal AFD/horizontal amp. I noticed that if I "flicked" one of them with my finger, the picture would jump. That seemed to happen to one particular tube no matter what position it is in. Moving it seemed to fix the top of the picture on the CRT "bending"..could be coincidence. Seems like one of the 6SN7GT tubes might have an issue, so I'm going to look around for a few NOS to buy.

Cary,
Whatever you do, please hold off on any idea of shooting the CRT with a 'juvinater. It's very easy to wreck the tube, specially if you don't have prior experience using one. If the tube is actually weak (which hasn't yet been proven conclusively), a brightener is the much safer way to go, for a noobster.:D

it might be bending at the top because of the tape , tapes have that effect on some sets , the white lines being stationary sound to me like a weak crt , its because you have to push more brightness then required and its showing up .

agreed it wont hurt to try a brightener and if it looks much better you will have your answer , on rare occasions you can run a set with a brightener for lets say an hour , remove the brightener and it might work ok without it after that but that's rare
there are series and parallel brighteners , I can't think at the moment but I think you want a parallel , someone correct me if I'm wrong.

If your heaters are wired in parallel you want a parallel brightener, if they are series go with series. Don't use one that is an 'isolation' type unless your CRT has a heater-cathode short.

Retrace lines can be an indicator of, but are NOT definitive proof of a bad CRT and can occur in a set with a perfect NOS CRT if the circuits are malfunctioning, poorly adjusted, or poorly designed.

The blanking circuit is usually a resistor/capacitor network going from near the output of one or both deflection circuits to one of the video stages. It feeds back the retrace portion of the pulse to the video stages turning them off HARD on the retrace.
If those parts have drifted in value or failed it can cause retrace issues. Some sets had the circuit, but it was insufficient or ineffective if the CRT emission changed slightly. If your set has an AGC control (when mis-adjusted it can cause retrace lines) I'd try adjusting it in conjunction with brightness and contrast to see if there is a good compromise that reduces retrace lines.

CRT rejuvinators are a mixed bag. The newer/est ones tend to be gentle and some of them are nearly fool proof, but many of the older ones going up into at least the 60's use 'Atomic blast' (modern VK slang) rejuvination circuits that tend to destroy as many tubes as they help...Though dead tubes that the safer rejuvinators can't help sometimes will be fixed by an 'atomic blast' rejuvinators. Rejuved CRT's don't always last some need a mild rejuv every 5 years and it brings them back to like new, others come back to varying degrees and fall back or below what they were at within hours or days.

I took another look at Phil's write up of his DuMont restoration, and saw a photo of the "scan lines", and that is exactly what I'm seeing. Information overload apparently caused brain-fade. I usually remember stuff like that visually.

I also saw how his set suffered from lower-than-normal voltage from the high voltage section, which contributed to a VERY dim CRT initially. His fix involved replacing a bad 270uuf mica cap marked C245 on the schematic. Looking at my order sheet from "JustRadios", I see I ordered a couple of these...and remembered they were just for this purpose. I'll try replacing it in the AM and see what happens. Can't hurt since I already have the cap here.

Cary,
Whatever you do, please hold off on any idea of shooting the CRT with a 'juvinater. It's very easy to wreck the tube, specially if you don't have prior experience using one. If the tube is actually weak (which hasn't yet been proven conclusively), a brightener is the much safer way to go, for a noobster.:D


Don't worry about the rejuvenator. I'm not even close to seeing one in real life, let alone having one in my hands to fool around with. There's a few other things I'd like to try, involving adjustments and circuitry, first. I'm not even sure I know what I'm doing with that yet...after doing some reading I find I might have gone about adjusting the yoke and ion trap all wrong. And there's a couple of adjustments in the high voltage section that I have no clue about. One is a screw painted red, with a silver screw next to it. I'm going to have to read up some fine print in the Riders and SAMS to see if there's any mention of it.

Wow!

I didn't think changing out ONE mica cap would cause such a problem. I had a stable, if slightly dim, picture before. Now I can't get the picture to stabilize for more than a few minutes at a time. Adjusting gets the picture looking great, and then for no apparent reason, I lose it and get..well..the photo will tell the story. So now I have a BRIGHTER bunch of hash.

First picture, before the change of the cap.

Second picture, after.

I didn't think changing out ONE mica cap would cause such a problem. I had a stable, if slightly dim, picture before. Now I can't get the picture to stabilize for more than a few minutes at a time. . . . .
First picture, before the change of the cap.

Cary, if that first picture is not a composite picture with the CRT image and the cabinet from two different exposures, that is a good picture tube. Back when this set was made, most people watched TV in a semi darkened room! Most 19AP4's had a gray faceplate that absorbed a bunch of light to allow the set to produce a darker black in a lighted room and hide reflections. Even when new, that tube would not be nearly as bright as a modern tube.

I'm using factory numbers for the R113 and I am confused as to what your are talking about. Did you change C-245 the 270 µµf mica capacitor that goes between pin 4 of the 6SN7 and pin F of the horizontal transformer Z-210?

If so, C-245 will affect horizontal sync, but I don't see any way this capacitor could affect vertical retrace in your picture or the brightness (provided it did not change the width of the image.)

Have you replaced the 6SN7 that changed the picture when thumped? This usually is the sign of a shorted tube. If it now is in the sync circuit, it could well be the cause of our problem.

If C-245 is the part that you changed, you need to recheck all your changes for a wiring error, wrong value component or an over heated pin on the transformer while soldering, or a cold soldered joint.

Once you get the set back to working, for either retrace or lack of brightness on a set without traditional sweep blanking, the first thing I would check is the DC restorer.

My first check in the DC restoration circuit would be to measure the 1 meg resistor on cathode and check the voltages on that tube and also try a substitute 6AL5.

Where your retrace only shows at the top of the screen, usually this is caused by a wave shape error on the vertical sweep spike, although I've seen a gassy CRT do this. (The spike is the part of the sweep where the beam moves back to the top and if it slows down near the top, it often will be visible.)
Jas.

Cary, if that first picture is not a composite picture with the CRT image and the cabinet from two different exposures, that is a good picture tube. Back when this set was made, most people watched TV in a semi darkened room! Most 19AP4's had a gray faceplate that absorbed a bunch of light to allow the set to produce a darker black in a lighted room and hide reflections. Even when new, that tube would not be nearly as bright as a modern tube.

I'm using factory numbers for the R113 and I am confused as to what your are talking about. Did you change C-245 the 270 µµf mica capacitor that goes between pin 4 of the 6SN7 and pin F of the horizontal transformer Z-210?

If so, C-245 will affect horizontal sync, but I don't see any way this capacitor could affect vertical retrace in your picture or the brightness (provided it did not change the width of the image.)

Have you replaced the 6SN7 that changed the picture when thumped? This usually is the sign of a shorted tube. If it now is in the sync circuit, it could well be the cause of our problem.

If C-245 is the part that you changed, you need to recheck all your changes for a wiring error, wrong value component or an over heated pin on the transformer while soldering, or a cold soldered joint.

Once you get the set back to working, for either retrace or lack of brightness on a set without traditional sweep blanking, the first thing I would check is the DC restorer.

My first check in the DC restoration circuit would be to measure the 1 meg resistor on cathode and check the voltages on that tube and also try a substitute 6AL5.

Where your retrace only shows at the top of the screen, usually this is caused by a wave shape error on the vertical sweep spike, although I've seen a gassy CRT do this. (The spike is the part of the sweep where the beam moves back to the top and if it slows down near the top, it often will be visible.)
Jas.


You may have a point about me expecting more from the CRT than it was designed to deliver. I don't have any point of reference to compare to since I never have ever seen this set working before. I'm probably expecting too much from 1950! However, that image of the picture is with the brightness and contrast almost all the way up. Towards the middle of adjustment, it would fade to black. And I will say that the photograph does make the picture appear slightly brighter than it is in real life. But I did take that photo this afternoon, with daylight in the room.

According to Phil's write up of his RA 113, he experienced a dark picture because he wasn't getting the high voltage required. He states he was only getting about 4000 volts, when the tube was supposed to be getting around 12000, I may have misunderstood what he wrote, but he found the waveform associated with C-245 incorrect, which seemed to be associated with the voltage deficiency. I'm not real knowledgeable in this, so I was duplicating what he did.

http://www.antiqueradio.org/DuMontRA-113Television.htm

It did seem to work somewhat. I don't have any way at hand to check high voltage, but I do have some old electrical test gear out in the shed that I'm going to dig out tomorrow. I think on of the testers will test high voltage, but I don't remember how high.

You hit the nail on the head about the C-245 mica affecting horizontal sync. I found that little "extra" adjustment on the chassis, right next to the 6BG6G tube. Once I made the adjustment and got the picture back, it did seem to be a bit brighter. But I could be seeing things, and it was getting dark outside by then.

I don't have any spare 6SN7 tubes yet, nor 6AL5's. I plan on getting a stock together of extra tubes for the set, but haven't had time to to locate and order them all yet. I'll make sure to put 6AL5's on the list of "must haves" too.

This sure is a learning experience! You will probably get a kick out of my next post!

I agree that first picture is actually really good for an old set in what looks like a very well lit room. Any chance you kept the old mica cap you replaced? If so I'd try putting things back to original.

[edit] oops, I see you posted the cure for your problem while I was typing my message. BTW you've done an excellent job of bringing this set back to life. Not an easy task for a first time TV restoration.

Here's a good one!

Take a look at the photo and see if you can figure out what's wrong.

I've done that TWICE today! ARGGGGGHHHHHHH!

Gonna go take it apart again and retrieve the adjuster...again!

I did find out there's resistors in there! Another learning experience!

. . . . However, that image of the picture is with the brightness and contrast almost all the way up. Towards the middle of adjustment, it would fade to black. And I will say that the photograph does make the picture appear slightly brighter than it is in real life. But I did take that photo this afternoon, with daylight in the room.

You just casually mentioned what probably is the best clue yet on your brightness issue.

If the image blooms (it suddenly gets bigger as it dims out) before it goes out, look something restricting the HV current to the picture tube. This is the normal symptom of sudden high voltage drop. The most usual suspects are the 1X2 tubes. And no, you cannot test one 1X2 by switching it with the other one as they work together to form a voltage doubler. *

If he image does not bloom, and the image stays close to the same size, look for the problem in either the video output, DC restorer, brightness control or picture tube circuit or the CRT itself. (The latter is not too likely.)

* If you had a scope, you could confirm that the waveforms and signal level going into the grid of the horizontal output are correct. You really need a known accurate HV meter before you go messing with the HV adjustments.

Here's a good one!

Take a look at the photo and see if you can figure out what's wrong.

I've done that TWICE today! ARGGGGGHHHHHHH!

Gonna go take it apart again and retrieve the adjuster...again!

I did find out there's resistors in there! Another learning experience!

YIKEs dude. :eek::jawdrop:That looks like a video IF can. It has nothing to do with horz sync. Hope you can get the slug back to where it was. Hope you haven't turned any of the others.

Let me chime in and agree that your picture looks pretty darned good. 60-year old TVs are not like modern plasmas. They were watched in subdued light, not bright sunlit rooms.

It's possible that you are very nearly done. As old_coot88 recommends, I'd be very cautious about turning any adjusters unless you have identified them in the manual and you have a clear plan in mind. The video IF adjustments are critical and you should not touch them unless you have specialized equipment and the experience to use it.

Part of restoring a vintage TV is learning how a TV from those days actually works (for better or worse). You might want to sit down in the evening and watch the TV for a while -- give it a little shakedown cruise. How is the stability? Are you constantly jumping up to adjust something, or can you basically sit back and enjoy the show? What's the audio like? How does the TV audio compare to audio in FM mode? (The audio is usually louder in FM radio mode on this particular TV, but the quality should be about the same.) Take some time to get used to the continuous tuner, so you know when you have found the spot where you get the best picture and the best audio. If the best-audio spot is far away from the best-picture spot, then perhaps it would help to tweak the audio adjustments. And so on . . . .

Regards,

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

I do agree that I would have preferred to not have to adjust any of the IF cans. But that ship sailed decades ago. When I brought home the set from my grandparents house decades ago, the adjusters had already been tweaked, possibly many times. I found some were turned all the way out, some turned all the way in (hence the one the "fell" into the can a couple of times. It apparently no longer has the "stop" the others do). As a result, the initial picture was not as good as it is now. It was "blocky", and had a lot of "ghosts". My grandfather was a big "do-it-yourselfer", and my mother confirmed a few nights ago on the phone that he tried to fix it himself back in the 1960's, but I doubt he ever had the SAMS or Rogers references to start with. I spent a lot of time with grandfather, and worked with him in the construction biz back in the late 70's through mid 80's. I credit my grandfather for my "gumption" to tackle new tasks. When I was young, faced with some seemingly insurmountable task, and would ask "Can we really do it?", he would say "Somebody built it." or something appropriate, and we would dig in.

I would love to have the equipment to "set it and forget it". I'm hoping to have access to an oscilloscope and signal generator eventually, perhaps borrow them if I can find someone who has them, or even if it means buying them myself. Then I can follow the alignment directions in SAMS and be done with it. In the meantime, in order to get the picture I have, I've had to spend hours looking for the "sweet spots" and learning how the IF adjusters affect picture and interact with each other. Admittedly not the best way, but right now, it's the only way I've got.

I also followed the "AGC" adjustment and horizontal sweep adjustments in the SAMS (sans the equipment for the horizontal sweep, thus relying upon my best judgment of picture, of course) and it's all been good. In fact, that alone brightened the picture immensely. It will be interesting to see, eventually, how close I got.) One of my frustrations has been that the test pattern DVD made with files downloaded from the internet works great in the computer's DVD player, but won't play in any of the actual DVD players I've tried it in, so I'm having to make adjustments with static images from shows.

We watched a few hours of "Get Smart" last night and I did notice some bright white "blips" along the "scan lines" that faded away with warm up. But after a couple hours, during an episode that had much brighter backgrounds than others, they reappeared. Looks like I've got some more tweaking to do. Also, it seems the "scan lines" appear, quite faintly, against a dark background even when the brightness is turned down quite a bit. Interestingly, in the copy of the original "SAMS" folder I have, on the schematic someone had used a pencil to circle "C2" 50uf cap, and wrote "vert jitter retrace lines".

I know this is a long shot, but are there any "old time" do-it-yourself" processes for video alignment for folks who didn't have scopes and signal generators and such? I'm kind of having to make this up as a go along, but maybe I'm "re-inventing" the wheel.

And check out that brand-spanking-new eye tube! It's action seems correct, in that it does move maybe a quarter inch up and down when it's slightly "off signal". However, when it's not on a channel at all, it lines up pretty good as well. As I get to a a video signal, it moves either up or down, and then lines up again, apparently when I reach "center" of the best signal. Is that normal? I've read where the action of this particular eye tube is not very "intuitive"..especially considering the left bar's BOTTOM edge is the one that is supposed to move up and down...and I have to agree it's pretty funky.

I didn't get a photo of the lines on my TV, but they remarkably look a lot like this photo that I found on the 'net. I've now read that they appear to be a symptom of the old set trying to process all the info contained in a more "modern" TV signal. Is it just something to "live with"?

I think your set is looking pretty good. I didn't notice smearing on the picture of the GET SMART title. It's reasonably clear and sharp.

I can only hope that my RA-113 will look as good as yours. It's basically untouched, other than a screwy looking audio output transformer being installed in the past.

I think your set is looking pretty good. I didn't notice smearing on the picture of the GET SMART title. It's reasonably clear and sharp.

I can only hope that my RA-113 will look as good as yours. It's basically untouched, other than a screwy looking audio output transformer being installed in the past.

Thank you! I can only attribute it to a LOT of "dumb luck", and determination, considering I'm a total "noob" with no experience, no specialized equipment, and had been told for decades that a bad picture tube was why the set was "retired".

And I've even taken a couple pretty "zings" off the metal cone of that danged 19AP4 metal cone CRT! I'm glad our floor is well ABOVE ground level on a foundation. While not nearly enough to "knock me across the room", it certainly got my attention and evoked a couple of decidedly NOT "family friendly" exclamations.

Maybe another thing I inherited from my grandfather is that we aren't very good electrical conductors. I once watched him test a light socket to see if it was "hot" by sticking his finger in it...and after he declared it was NOT hot...I screwed a light bulb into it and it lit up.

On your set, was the audio transformer an "aftermarket" replacement? Or was someone trying to boost the audio or run an external speaker?

I know this is a long shot, but are there any "old time" do-it-yourself" processes for video alignment for folks who didn't have scopes and signal generators and such? I'm kind of having to make this up as a go along, but maybe I'm "re-inventing" the wheel.
.
OOOY VEY!! I don't know where to even begin on this. Even a seasoned techie, if he knew beforehand that all the vid IFs had been tweaked with, would have thrown up his hands and sed "No Way!"

Back in the day there was a shop that had a proficiency test for new hires. The boss would take a set and deliberately throw the vid IFs off. The applicant was expected to re-align it using the full suite of equipment (sweep genny, scope etc.)

The fact that you've got a watchable picture on the set is nothing short of a miracle and testament to your Granddad's indomitable spirit and admonition to "dig in and do it." It's virtually fulfillment the Sea Bees' motto:

The difficult we do immediately
The impossible takes a little longer.

My hat's off to you Sir. I would never have even attempted it.

The usual symptoms of misalignment are loss of fine detail in the pic, smearing-out and ringing of the vid signal. The best advice at this point would be to not try to "improve" upon what you've got.

I didn't get a photo of the lines on my TV, but they remarkably look a lot like this photo that I found on the 'net. I've now read that they appear to be a symptom of the old set trying to process all the info contained in a more "modern" TV signal. Is it just something to "live with"?

The lines in your posted picture are from copy protection on VHS or DVD material. Those shouldn't appear on over the air programming. I'm thoroughly impressed by the quality of your picture. You may be one of the very few who possesses a superhuman knack for visually aligning a TV's IF strip. :)

PM sent to CaryLee.

they appear to be a symptom of the old set trying to process all the info contained in a more "modern" TV signal. Is it just something to "live with"?As Kevin noted, those look like interference from Macrovision or a similar copy protection scheme. Here's one of my TVs displaying similar lines when I played a copy-protected DVD:

http://antiqueradio.org/art/MacrovisionInterference.jpg

The lines disappeared completely when I played a non-copy protected DVD. To confirm that's what you have, play a non-copy protected DVD or hook up some other source (VHS player?) using non-copy protected material.

Retrace lines look different; they slant all the way from one side to the other. Here's one of my TVs with and without visible retrace lines (I'm using a little test CRT, not the TV's native picture tube):

http://antiqueradio.org/art/Philco49-1240RetraceLinesAfter.jpg

http://antiqueradio.org/art/Philco49-1240RetraceLinesBefore.jpg

Retrace lines generally disappear when you turn the brightness down beyond a certain point, while Macrovision lines are less affected.

Phil Nelson

I know this is a long shot, but are there any "old time" do-it-yourself" processes for video alignment for folks who didn't have scopes and signal generators and such? I'm kind of having to make this up as a go along, but maybe I'm "re-inventing" the wheel.



The fact that you've got a watchable picture on the set is nothing short of a miracle and testament to your Granddad's indomitable spirit and admonition to "dig in and do it." It's virtually fulfillment the Sea Bees' motto:

The difficult we do immediately
The impossible takes a little longer.

My hat's off to you Sir. I would never have even attempted it.

The usual symptoms of misalignment are loss of fine detail in the pic, smearing-out and ringing of the vid signal. The best advice at this point would be to not try to "improve" upon what you've got.

There are a few "cheat" like alignment techniques. The SOP for most sets is to use a FM sweep generator(only a TV specialized version there of), an AM signal generator for markers, and an O-scope, but early on some makers published data on how to do it without the sweep generator on some sets...

A slightly better cheat (if you no gots test equipment) was IIRC was originally described for the Sencor VA-62. One can attempt to visually align the video IFs of a set if it is displaying a 'multiburst' test pattern which is basically a pattern of black and white vertical bars that become thinner from left to right. If you align your set with that pattern (and a audio test tone to make sure you don't kill the sound while working on the picture) I believe the procedure is something to the effect of get the thick bars clear, then try to get progressively thinner bars clear while keeping previous ones good.
The thickness of the bars basically corresponds with the frequency they produce so the thinner the bar the higher the frequency (it is often used to test video response in home theater applications). You could probably buy or burn a test disc with a 'multiburst' pattern cheaper than you could get the right equip for the factory proceedure.

Personally I tend to agree with coot on not messing with it any further, but if you are not worried about messing up your progress trying to get more or just want a yard stick of how good you did then the multiburst method may the thing for you...

Macrovision is inserted in the vertical sync space as a series of white video dashes at about 140 units of video. They time in and out on the insertion which explains why your set wonks out and then returns to normal for a bit. When your ancient set sees it, the AGC kicks in and collapses the video to take the 140 down to 100 units of video. This in turn collapses the underlying 40 units of sync down to something unuseable by your set. About 20 units or so and not enough to give you a good pic.

One old cheap solution is to find an old Betamax. Very old. They inserted new sync on the output and that will help the issue. Send your air/cable/video signal to the Betamax and use its output as RF 3/4 for your set.

...but if you are not worried about messing up your progress trying to get more or just want a yard stick of how good you did then the multiburst method may the thing for you...
If i were Cary, i would absolutely stop at this point and consider it a badge of accomplishment. :thmbsp:
If i really wanted to pursue barefoot alignment techniques, i'd get a beater set rather than risk doing it on an irreplaceable family heirloom.

If i were Cary, i would absolutely stop at this point and consider it a badge of accomplishment. :thmbsp:
If i really wanted to pursue barefoot alignment techniques, i'd get a beater set rather than risk doing it on an irreplaceable family heirloom.

I agree. I could not have said it better myself. Since this is a family heirloom and you do not have the the equiptment to do alignment on this set call it good for now. It's not worth making things worse. the picture looks good to me. I often have to show patients and give myself and the project I am working on a rest. See bandersentv video on Dumont restoration and alignment there is alot to it. Enjoy and be proud of the good work you have done.

if your still having line issues and brightness issues I'd still say the crt needs to be checked or a brightner added to see what you get , my ra-109 has a weak crt and will function without a brightener but you have to push the brightness to get a decent image and the retrace lines appear , with a brightener it takes less to push the brightness , the lines do not come in as easily and the whites are brighter along with blacks that are blacker , also you don't lose focus as easily either when brightener is added , since I have a crt tester I can see what the emissions are so this told me what to do, this it too why I added a resistor so the brightener isn't pushing its full voltage into the crt because at 7 volts emissions rise making it a decent picture , it does require a couple minutes of warm up before the focus and brightness come up but it is better to not over push the crt and have a warm up then to hit it with full voltage all the time.
so without a crt tester you don't know whats going on but you could try the brightener , it wont hurt , me and a friend have tried them on good crts in the past and saw no difference but when added to a weak crt a difference is seen , this is just a suggestion , I recently tried one on a color crt that tests good just to confirm a couple guesses from others that maybe an issue I had was the crt , it made no difference to its performance and was removed.

Well, I'm still pretty new to all this and I've never even touched a DuMont before, so I can't comment on anything techical here. Following this thread has been really interesting and I admire Cary for all that he's done. It's a great job to get this far and an inspiration to newbies everywhere.

The discussion is starting to remind me of what happens with a lot of car guys. They get their car repainted and then worry over a minor imperfection because they're so close to it and want it to be totally perfect. However, nobody else ever notices and can barely see it even when it's pointed out to them.

The truth of the matter is it's impossible to get something totally perfect and it wasn't even that way when it was new. Just go to a new car lot today and really look over the cars and you'll see lots of flaws.

Of course I'm not seeing the DuMont in person so I might change my mind if I did, but the pictures look pretty darn good even if it is a little darker. I would say a few things to keep in mind are:

A) This set probably wasn't perfect when new.

B) It was designed to pick up weak over the air signals that an owner in 1950 might have only been able to get with a huge antenna, a lot of static, and only at night if they were far enough out. They would have considered it good if you could even see a face.

C) They ain't makin' parts or CRT's anymore, so I say unless it's for daily use, get all you can out of the existing stuff.

D) I bet everybody you show it to will oohh and aahh over it, congratulate you on a job well done, and never even notice the imperfections. And, if somebody does, just mention points A through C above, or tell them to go buy their own DuMont and see if they can do better!

Finally, somebody above mentioned just sitting down and watching the set for a couple of hours and see how you like it. Watch it as if it was a regular tv, not a family heirloom. If it's still objectionable to you, then try tweaking it.

I think a good test might be to throw in a Girls Gone Wild tape and after the end of it you're still noticing the lines, it might need adjusting.

I dunno. Considering the heirloom status of the TV, and unless the CRT is absolutely and equivocally proven weak and needing a brightener, i wouldn't do it. The pics Cary has posted of the CRT's display sure don't look like a weak CRT.
Symptoms of weak emission would include (from a cold start): coming on very dim with a 'silvery' or negative look, then gradually building up over several minutes to a brighter pic.

Yeah, the contrast on the below picture is excellent considering the room lights are on. The dark area's simply can't get any darker than the CRT face color when the set is turned off. The whites look very bright, and there's no visible retrace lines that I can see. IMO it's as good as it can get from an 19AP4. Turn the lights off and you can turn the brightness down accordingly. Kick back and enjoy. :thmbsp:

http://videokarma.org/attachment.php?attachmentid=181744&d=1392130928

That picture looks wonderful! Nothing like seeing a good working DuMont and you are lucky to have one. Just get some help when moving the thing!

Nice job Cary! I'm new to TVs and you're giving me hope. Looks Great!

I just remembered although it may not apply in your case , the ion trap if not in the right position would cause less brightness , unsure if you ever checked it or not
mike

GOOD CALL on the ion trap. One of us geniuses shoulda thunk of it earlier.:nerd:

Howdy all,

Thanks for all the kudos on the DuMont! I appreciate it. Working on this set has certainly given me the confidence to do another, though it's more likely to be a tabletop model, unless something else falls into my lap out here in New Mexico.

Thanks for the tip on the ion trap. That is one of the first things I learned about to get the brightness up. The one on my set is just a magnet on a collar with a spring around it, no tightening mechanism, so it's also easy to accidentally knock it out of adjustment with just a touch...which I've done a couple times and then panicked as I wondered for a second why the picture got so dim suddenly.

I've taken a break from the DuMont to work on a few other projects. Doing some remodeling in the house and have to get the engine back in my Jeep Wrangler. It's been a "short block" sitting in the cargo area of our van for a month and a half now, and I've got an off-pavement trip coming up first week of April. AND, we've got nice weather right now...daytime temps in the 60's! Can't beat that for February, particularly considering the hammering the rest of the country is getting from the weather. I have to take advantage of it.

Back to the DuMont for a minute: I do have some NOS 1x2 rectifier tubes for the HV power supply in my mailbox, gonna pick them up this morn and see if it makes any difference when they are installed.

The only major issue I seem to be having with the DuMont right now is that I seem to have the picture well aligned, and in fact pretty good, but slightly off from the best sound alignment. The sound volume doesn't get very high at it's best when I adjust the sound IF cans, and there's plenty of "hum". I've gotten louder and clearer sound when the picture wasn't as good...makes me wonder if I don't have every single video IF can off by the same amount, so I get good picture, but they are too far from the range of the sound IF cans. There does seem to be some correlation, however slight, between picture and sound on this DuMont, even thought they are technically "split".

It will be something to tinker with in the next couple evenings as I finish up some other projects.

I'll certainly keep everyone updated, and thanks again for all the help and encouragement while I've been working on this DuMont! I'm very happy to have it back in the house for the first time in a decade, and operational for the first time in half a century!

Cary,
Unless somebody can advise otherwise, i would hafta say this regarding your sound tracking problem: The problem lies entirely with the sound IF strip, not the video. Any misalignment of the video strip would show up visually (as smearing, ringing, loss of fine detail etc.). Please resist any temptation to touch the vid cans any more. :)
I would try "walking" the sound cans a bit in one direction, and if tracking gets worse, 'walk' them in the other direction. 'Walking' each slug involves going only a tiny fraction of a turn at a time.

Cary,
Unless somebody can advise otherwise, i would hafta say this regarding your sound tracking problem: The problem lies entirely with the sound IF strip, not the video. Any misalignment of the video strip would show up visually (as smearing, ringing, loss of fine detail etc.). Please resist any temptation to touch the vid cans any more. :)
I would try "walking" the sound cans a bit in one direction, and if tracking gets worse, 'walk' them in the other direction. 'Walking' each slug involves going only a tiny fraction of a turn at a time.

I will definitely try your suggestion. Thank you! I really would rather NOT have to fool with the video strip again if I can help it, at least until I have access to an oscilloscope and signal generator.

I don't know if I ever mentioned that it took about 8 HOURS, over two days, to get the picture to where it is now, strictly going by eye. I'm definitely not enthusiastic about doing that again.

you may have to do what I had to do to my Dumont , similar issue with the sound , so I hope I'm correct in what I'm about to say , if not someone correct me ... let the set run and warm up for about 10 minutes , tune the picture to where it looks best and then do what old coot said and go one by one with the sound alignments , eventually you should be able to get them to where the sound is the loudest where you are tuned to a good picture , working with the sound if alignments should be easier then doing the video ifs.

This kind of divergence is common with "split sound" TVs like this, where the sound signal is picked off fairly early and the audio section has its own series of IF amplifiers, in parallel to the video IF amplifiers, so to speak. (An alternative, slightly more modern design is to pick off the audio signal farther downstream, after the IF amplification has been performed.)

Look carefully at the schematic and your manual's sound alignment instructions, and you should be able to do what old_coot88 says: gently nudge the audio IF alignment to match up with your current video IF alignment, so that they both tune in together. I think you will find it considerably easier than video alignment.

Phil Nelson

Cary,
You gotta realize that the normal video IF bandpass is extremely wide, and the individual cans are actually stagger-tuned to different frequencies within that band.
Whereas the sound IF is tuned to only *one* single frequency and is extremely narrow compared to the vid IF.

This is why no amount of tweaking the vids is gonna shift their tracking 'toward' the sound.

Whereas shifting the sound IF centerpoint relative to the vid will change tracking.

here are some pics of the sister to your Dumont , the ra-109

on this RA-109 I have please look at the crappy cell phone pics that I took while running out the door, . I though it was my eyes but even my cell phone shows this.
since Everyone is talking about Dumonts and 19AP4.
is there something different about the Phosphors in these tubes?
its perfectly Focused, its just a crappy cell phone picture, and the camera white Balance is fine,
I will take another pic with my Nikon DSLR later afterwork. but for sure with my eyes its Bluish

One of my cameras makes B/W screens look very bluish. I think some of it has to do with shooting under comparatively yellowish indoor lights. The camera does some kind of color average (is that the right term?) with the room as a whole and gets the colors right for the cabinet, drapes, etc, but the screen comes out too blue. It's so blue that, for photos I want to use on my website, I sometimes cut out the screen portion and convert that to greyscale so that it doesn't look ridiculous. This effect is true of all my B/W sets, with various CRTs; they all display shades of grey to my eyes but the camera turns them weirdly blue.

Try turning out all of the room lights and taking a photo of only the screen. Then turn on the room lights, photograph again, and compare blueness of the screen in both shots.

I'm not saying that phosphors don't have different colors, only that I've seen this very obvious effect when shooting photos under warm indoor lights.

Phil "not a serious photographer" Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

This is a afternoon shot with a Nikon DSLR this time
This is a NOS 19AP4, guess I should have left the sort of weak one in.

When was that NOS 19AP4 made?

I know there are differences between tubes made in the 40's-50's, the phosphor is a uniform color, B&W tubes from the 60's-70's seem to have a different formula, if you look at them up close while on you can see yellow and bluish colors in the mix. I would assume it was done to make the image look brighter, like adding Bluing to wash makes it look whiter.

here are some pics of the sister to your Dumont , the ra-109

Wow! That's a rock-solid, dead on, straight and uniform picture!

I still have a couple issues with the adjustment on mine..sometimes people's foreheads and hairdos seem to get a bit bigger towards the top of the screen.

I tried my test pattern disk in a newer DVD player and it worked. It won't play in the older dvd player I have hooked up to the DuMont. Now I have to decide if I want to go through the hassle of unhooking the newer DVD..it's pretty tough to get to the wires, and there's a 30 gallon aquarium on one end of the hutch it is in..so easily moving the furniture to get to the wires in not an option. I might have to commandeer my son's Xbox 360 temporarily to use as a DVD player...if IT will play the disk.

This is a afternoon shot with a Nikon DSLR this time
This is a NOS 19AP4, guess I should have left the sort of weak one in.

I don't have much to add having little experience with various CRT's. It does look kind of bluish in the photo, but it is a good clear picture. I wonder if you would notice the tint if you didn't have anything to compare to?

Do CRT's have a "break in period" when they are new? Might it settle down a bit with use?

I'm still curious to see what it looks like in total darkness. Hold the camera right in front of the screen and photograph nothing but the image on the CRT (not even the green tuning eye).

Phil Nelson

White P-4 phosphor on early CRTs is actually a mixture of two different phosphors. One component is yellow and the other is blue. Combined in the correct ratio the mix produces a decent, fairly uniform white.
Sometimes I have observed, when re-installing a round P-4 CRT after work on the chassis, that orientation of the CRT is critical otherwise "blueish" areas of the CRT are illuminated. I suspect that the blue component of the P-4 phosphor ages more rapidly, and over time the used areas of the tube become "warmer" or more yellow. Likewise, I would postulate that a new P-4 CRT would very likely be bluer than a well used one.
jr

I think Phil is correct that it has to do with light balance in the room. Here's a couple shots(bad focus) of the 19AP4 in my Sentinel. Notice how when more of the back lite room is showing that the picture takes on the blueish tint. Somehow I always end up with a reflection of my GE clock on the screen.

http://i452.photobucket.com/albums/qq245/Kuehn/Sentinel%20525/Sentinel5250073_zps40a77fdd.jpg?t=1393091979

http://i452.photobucket.com/albums/qq245/Kuehn/Sentinel%20525/Sentinel5250072_zpsb854e071.jpg?t=1393005792

Sometimes I have observed, when re-installing a round P-4 CRT after work on the chassis, that orientation of the CRT is critical otherwise "blueish" areas of the CRT are illuminated.That reminds me, I saw that effect when I reinstalled a CRT in my RCA T-100. What's causing those faint blue areas on opposite corners, I wondered? Then I realized that if I rotated the tube and reduced the height to normal, they would exactly match the areas never scanned by the electron beam. The center portion that had been scanned was warmer in color.

The color difference was subtle. It didn't really register in a photo unless I cranked up the contrast & brightness beyond normal levels, high enough to make retrace lines.

Phil Nelson

http://antiqueradio.org/art/RCAT-100PurpleCRT04.jpg

sorry been busy, but No it's blue with my eye as compared to the old one, I know white balance all too well as I worked on in Broadcast Video Service and Working for the Packers in Replay.
I noticed this right away after I was just bored and replaced my old Slow warming 19ap4, I only did this because I had 2 N.O.S Tubes from the same person, not Rebuilt but NEW from Dumont but like 3 years newer or so..its a pain to replace, and you get used to it but I noticed the Blue right away.
here is a pic from the same set before and using the Exact DSLR Camera with the old original CRT .
I'll just have to get used to it, maybe for kicks I can push a RCA 630TS next to it and Take a few more pictures and compare.
but it seems that I remember someone Noting the same thing many years ago on this site, like 12 yrs ago or so. but my eye notices in person that its blueish for sure
Also maybe it does have to be Aged in like others have Said, I'll run it for hours and see. and I have found out that you can't blast away the Contrast or Brightness or you will get Retrace. I had pulled the whole chassis and checked it out, these Tubes for sure are not super Bright, it would be nice to find an Aluminized one, but those must be rare, I know they were made that way, I think Tung Sol shows it listed

I remember seeing B/W sets in the showrooms of department stores back in the day, and noticing the differences in the shading (color) of the CRT's on them.

We had a GE 19" set from around 1963 that was literally blue-white looking.

Maybe you have a 19AP4A or 19AP4B which have grey tinted/frosted faces ?

sorry been busy, but No it's blue with my eye as compared to the old one, I know white balance all too well as I worked on in Broadcast Video Service and Working for the Packers in Replay.
I noticed this right away after I was just bored and replaced my old Slow warming 19ap4, I only did this because I had 2 N.O.S Tubes from the same person, not Rebuilt but NEW from Dumont but like 3 years newer or so..its a pain to replace, and you get used to it but I noticed the Blue right away.
here is a pic from the same set before and using the Exact DSLR Camera with the old original CRT .
I'll just have to get used to it, maybe for kicks I can push a RCA 630TS next to it and Take a few more pictures and compare.
but it seems that I remember someone Noting the same thing many years ago on this site, like 12 yrs ago or so. but my eye notices in person that its blueish for sure
Also maybe it does have to be Aged in like others have Said, I'll run it for hours and see. and I have found out that you can't blast away the Contrast or Brightness or you will get Retrace. I had pulled the whole chassis and checked it out, these Tubes for sure are not super Bright, it would be nice to find an Aluminized one, but those must be rare, I know they were made that way, I think Tung Sol shows it listed


Wow. That is a georgeous TV.

Carl

OK here We go, 3 Pictures to amuse you :)
a 630ts to the left and the last picture notice the White cat.
sort of a pain to push and move all this.
I never looked to see if it had a Tinted face..I think they are a A version
one of these tubes was mounted in another set, but was not used so I am confused about the tint.
it's Noticeable in my eyes.
but Really a grey tinted face would Give a Blueish tint?
I should have posted a new thread about this instead of posting in Gary's thread, but didn't know it would go this far

Wow. That is a georgeous TV.

Carl

What he said !

One good way to judge color is to stand back from the set in a dark room and see what the CRT is doing to illuminate the room. Is it bluish or greyish? The poor cameras are working overtime in a dark room trying to make something white...walls, lamps or the white Persian cat can all throw it off. Try taking a photo in a manual white balance set for cloudy...a higher kelvin temp closer to a CRT. This will fix the camera on a specific kelvin temp setting and you can then see what your CRT is doing in that neighborhood. It will also throw the surroundings very red as it tamps down the blue.

And on the sound IF tweek. Which is the best direction to adjust by ear? From the split to the end amp or backwards from the amp? And upper or lower adjustments first if the can has both? I did this with a Pilot TV-37 set to a good pix and had good luck going from the beginning to the amp.