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:

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.

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?

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.

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.

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.

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.

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!

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.

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.

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?

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.

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.

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...LinesAfter.jpg

http://antiqueradio.org/art/Philco49...inesBefore.jpg

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

Phil Nelson

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.

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.