A Once in a Lifetime Dream Project
 

Hi,

some weeks ago, I got a surprising telephone call. I was asked to restore a German Telefunken mirror-lid prewar tv set from 1937, and to bring it into working condition. I was unsure whether I have the skills to do such a thing. I was afraid about the handling of the prewar picture tube. But nevertheless, I said yes. Two weeks ago, I got the set, and is in good condition. Unfortunately, the E.H.T. connector at the picture tube is broken (see photo). The picture tube itself is still under vacuum and has still silver getters. The filaments are also OK.

The set was upgraded to 625 lines in the 1950s. I have rebuild it back to 441 lines television standard.

The original line output tube, an AL5 special, is missing and hard to find. It was replaced by a 6DQ5. I hope that I can get an original AL5 special tube with the plate cap.

With the help of Darryl's World Converter, I could operate the set. Here are some pictures and a video:


http://fernsehmuseum.net/telefunken/img/FEVI_1_01.jpg
http://fernsehmuseum.net/telefunken/img/FEVI_1_03.jpg
http://fernsehmuseum.net/telefunken/...I_chassis1.jpg
http://fernsehmuseum.net/telefunken/...I_chassis2.jpg
http://fernsehmuseum.net/telefunken/..._1_Ablenk1.jpg
http://fernsehmuseum.net/telefunken/img/FEVI_1_CRT1.jpg
http://fernsehmuseum.net/telefunken/...nodenkappe.jpg
http://fernsehmuseum.net/telefunken/...emodulator.jpg
http://fernsehmuseum.net/telefunken/...VI_1_Spule.jpg
http://fernsehmuseum.net/telefunken/..._1_Screen7.jpg

Video:

http://www.youtube.com/watch?v=3kL5xE4aWko

Kind regards,
Eckhard

Wow...Just wow.

Hello Eckhard,

An amazing set and an amazing job you did on it, Wow!
And Thanks! for some great, high-res photos.

Are you going to post a restoration journal on your site?

Is the TV still operating on its original AC derived EHT transformer, i have heard from other pre-war set restorers that 95% of them need to be rewound.

And on the same topic, not too scared working near this high power "Neon sign" transformer? filter capacitor discharging before working on the circuitry must be quite spectacular...

Any ion burns on the CRT?

Best Regards

jhalphen
Paris/France

Is the mask more square than the usual 4x3 rectangle? If so, is it a function of the timing of 441 lines?

Dave A

That is amazing! Great job, very neat work!! There are more parts in that set than in half of my sets put together.

Very impressive set. A true collector's piece. :yes:

Wow...Good Work:thmbsp::thmbsp:

That is absolutely incredible. To think that this actually survived the raveges of WWII. I would love to hear the history and background of this set. Where was it used originally? How did it survive the war and where was it discovered? It seems to be in remarkably fine original condition.

Was it restored previously by another collector? Must be worth an absolute fortune.

Some conductive paint or epoxy carefully dabbed at the spot the broken off metal pin is, connecting to some high voltage wire, may be sufficient to pass the several microamps of high voltage current.

Eckhard:

Deine Arbeit ist ausgezeichnet!

MfG,
Steve

Cool, is that last pick Jamie from Myth Busters?

Jumpin' geewhillikers, isn't that something!

How does the EHT supply work? That looks like a high-frequency coil in
http://fernsehmuseum.net/telefunken/...VI_1_Spule.jpg

You make it look so easy! Incredible set...a million thanks for sharing with us!

That's absolutely gorgeous!

Having to work on the broken EHT connection would have made me a nervous wreck.

Congratulations on your accomplishment!

John

Hello all together,

thank you for all your comments! There are a lot of questions, I try to reply to each other without mentioning the writers:

Yes.

The set still operates with the original AC derived E.H.T. transformer and with the original E.H.T. capacitors. Both are positioned in a closed can with transformer oil.

There is a blocking resistor of 10 MegOhms, which discharges the E.H.T. rapidly after switching off. In the beginning, when I worked on the broken CRT E.H.T. connection, there was a connection of the E.H.T. with the black coal outer coating of the CRT. It is isolated from the chassis, so it has full E.H.T., and when I adjusted the picture centering, I touched it with my hands. ... You can imagine how I felt in this moment...

No. Only a nearly unvisible small spot in the middle of the screen. The CRT is working with 8 KV E.H.T., and it has electrostatic focussing and magnetic deflection. Additional, this set has already a damper (CY1 spez) in the line output unit.

Yes, it is. The mask is for the German 6:5 aspect ration format.

I don't know the history. Most of these sets were used in "Fernsehstuben" (public viewing rooms) in Berlin before the war, and with WW2, in hospitals for wounded soldiers. Some few sets were private. This set here was "upgraded" in the 1950s for the postwar 625 line television standard.

Most of the few German prewar tv sets were destroyed, or carried of to Eastern Europe. In the last two years, I got reports about three newly discovered German prewar sets, and I think that there are still some undiscovered in Poland or Russia, or even in Germany.

Yes. It was fitted with a transistor video amplifier for composite input twenty years ago.

No, it was taken from the actual aired German television program.

Yes. But much more nervous was the handling of the CRT. You can lot lie this set on a side without removing the picture tube. The high weight of the deflection yokes would break the neck. So, you have to remove the picture tube. I have loaned a helmet with a visor from our electrician, and weared a winter coat and leather glows when doing it.

Kind regards,
Eckhard

Simply amazing restoration Eckhard! That is one of the finest examples of ETV you have there. I'm glad there are others out there taking care of these beauties.

Beautiful set!

What an astonishing set.

My hands would have been trembling while working on such a treasure!

It would be interesting to see a schematic diagram.

Phil Nelson

Hi Phil,

here are the actual schematics of the set including the changes, I have registered:

http://bs.cyty.com/menschen/e-etzold...Schematics.jpg

Note, that the AL5 spz. and the CY1 spez. are replaced by a 6DQ5 and a 6AF3, until I get the original tubes.

The set will leave my home in the next week :-(

Eckhard

Eckhard,

Beautiful, simply beautiful. What a rarity. Are there any more than maybe 1 or 2 other working examples?

I am in awe of what some of this board can do to bring these old beauties back to life. :tresbon:

That is a fantastic set. Just curious, is in in a museum, or a private collection?

Hi,

There are IMHO ten surviving FE VIs today, you can find them photographed and listed on

http://fernsehen.bplaced.net/ind_tel.html

I know of another one of them, which is in working condition, you can see it even with a raster here:

http://www.drm-berlin.de/museum/2007/2007.html

The FE VI is the nmost commonly survived prewar set of all German prewar tv sets.

Kind regards,
Eckhard

I would be more nervous than a cat in a room full of rocking chairs tryin' to work on that bad boy...

This is the raster which appears on the screen without an antenna signal. I have got the same raster before I tuned in the channel.

This is an interesting observation Eckhard. Looking at the schematic it appears that the line and frame oscillator stages use blocking oscillators, so I would have expected the set display a normal blank raster. What do you think is causing the displayed raster to look like this when no signal is present?

The height of the synchronisation input level can be controlled by the 5 K control at the cathode of the oscillator tube. My experience is, when I have adjusted the sync level for best synchronisation, and I draw the antenna plug, the raster looks frazzled.

Eckhard,

Really appreciate you sharing this unusal and rare receiver restoration. The set really reflects German prewar attention to detail in design and engineering. I am especially intrigued by the modern looking, metal framed, rectangular control panel (?) above the Telefunken name.

-Steve D.

Steve,

this control panel has only two switches. One switch is for sound (Ton), the other for vision (Bild). You can use this set as a radio, when switching on sound (Ton). When you switch on vision, the vision power supply, the valves of the vision I.F., video demodulator and the deflection units are heated, and the E.H.T. transformer is activated.

Kind regards,
Eckhard

Fully-functioning 70 & 80 year old radios are commonplace on this site....but a working 72-year old television??? Congratulations on excellent work!

My next project will be a 81-year old television ;-)

Gorgeous and fascinating set, amazing restoration... On behalf of humankind, thanks for restoring that, and for sharing it!

:ntwrthy: :ntwrthy: :ntwrthy: :thmbsp:

Amazing!!! Impressive!!! To see such an ultra-rare and fine piece of History in WORKING condition... is something that really makes my day!!!

Hi @ All!
Well done Eckhard.
To see this set in operation is a pleasure. The owner is a lucky man. The video is shown on youtube is really impressive.
And that's the reason why I like this set so much:
The company where I was working for eight years since I was 16 had such a set too. Unfortunately there were many missing parts like the cabinet, the loudspeaker and some tubes. The CRT and both transformers were still in place. I never dared to touch this set and so a can`t say anything more. After the company went bankrupt I never saw the set again. I hope it was not demaged and came into good hands.
Greetings Josef

so you could get just the TV audio? cool feature i think!

Hello.

Yes, I can select between tv audio and tv audio and vision.
In times of no television broadcast, the television transmitter was used for radio broadcasting.

Here is another video, I have recorded today with some still images from the chassis and a short video clip. See the color of the phosphor. The white is a yellowish white, not that blue-tinted white of modern P4 phosphors.

http://www.youtube.com/watch?v=eAHnJqaD06A

Meanwhile, the number of surviving Telefunken FE VIs increased up to ten. As a result of such videos on Youtube, other people reported further FE VIs which existence was not known before.

Kind regards,
Eckhard