Using old camera tubes with modern electronics
 

G'day all.

Quite a few years ago I wondered about the possibility of someone recreating an ancient broadcast camera from the pre-60s era using an original IO or iconoscope camera tube and drive it with the modern electronic equivalent to the original circuitry to get it crankin and producing pictures like it did back in the day.

Then I came across this site http://www.golden-agetv.co.uk/ and discovered somebody has indeed done this with an iconoscope camera tube dating 1948 as seen about 1/2 way down on this page http://www.golden-agetv.co.uk/equipment.php?FromID=1 .

http://www.golden-agetv.co.uk/img/equipment/143b.jpg

Now this makes the wonders of possibilities of recreating a number of old tube cameras using the original tube and modern electronics, such as recreating a typical 40s/50s IO camera, a 3 IO tube TK-41 type colour camera, a 30s emitron camera, possibly even a later refined Farnsworth style image disector tube camera that makes pictures.

Just an idea for any of you who are technically minded and have access to these old camera tubes to build an old tube camera with modern electronics to give the younger generation a true idea of how TV pictures looked way back in the 30s to 50s era.

Cheers
Troy

Wow....Just "Wow"....

Wow indeed! The golden-agetv site in the link has an amazing collection of vintage gear for rent. They even throw in an engineer to operate it for you :D

Than again - I suppose I would too. How many folks would have any idea how to use any of this stuff :scratch2:

I ain't got a clue on how to work it, but Dah-Yum, wouldn't it be fun to play with for awhile...I'd STILL like to have a TK-41...I have absolutely no use atall for the damthing, I just think they're Kewler than all get-out....And of course, it'd HAVE to have the Houston-Fearless dolly/cradle, & Zoomar lens...I mean if you're gonna Go For It, you may as well GO FOR IT !!!

Jay Adrick (now at Harris) told me that when he was at Xavier University, they inherited some TK-41s from a local station. He said replacing the signal electronics with solid state circuits resulted in an 8 dB improvement in video signal-to-noise ratio.

The guy in the photo is Paul Marshall, one half of Golden Age TV. I have known him for many years and seen his huge collection of stuff. This includes 2 fully working multi-camera outside broadcast trucks (remotes to you guys in the US) He tells me he is about to start a massive project to restore a 3rd truck from little more than a shell into an fully working early OB truck.

Apart from hiring out props, Paul takes his trucks to various events including the Lincoln Steam and Vintage rally where they get a lot of attention.

Well, I think its absolutely GREAT that there are a few iconoclasts out there "Keeping the Dream Alive", as it were...

Hi Troy

I think the big problem is finding your tube, The tube used in Paul's camera is a Pye Photicon or possibly a Pye PES Photicon, or, in plain speak, a midget image iconoscope tube. These are like hens teeth to get hold of in the UK. The availability of Iconoscope tubes is better in the USA, still expensive and best collected!

Image Orthicon (I.O.) Tubes are much more common and several people have constructed cameras using them. See CQ-TV 89 to 91 downloadable from the BATC site, www.batc.org.uk for an example.

Attached is a picture of a home built 3 plumbicon camera compete with home made light splitter (mirrors + filters).

Regards, Brian, www.tvcameramuseum.org

Wow thanks for that Brian, am checking out the past issues. Looks like in issue 89 they have given all the circuitry diagrams to drive an IO tube so you can build a 50s IO camera with 1975 electronics to drive it.

I just stumbled across a picture of myself on this board with my Image Iconoscope camera. That picture was over ten years ago, 1997, I think.

Some more information on this project might be of interest to readers.

The hard part was not finding the Photicon tubes (I now have four), but finding out how to drive them. I had some help from a BATC member who used to work on Pye Mk2 cameras which used these tubes, but it wasn't enough to be able to work out the exact requirements. Designing and building/winding the two focus coils (image and beam), plus the deflection coils was tricky. These needed to be low voltage types compared to the original high voltage valve drive ones. The relationship between the rotated image section and the offset electron gun caused much grief as the strength of the focus field alters the rotation (of course). Then there was the 'diddle magnet' that nobody knew about, needed to align the electron beam properly. The video output from the target was only 20 mV - I wasn't expecting that either! The heater voltage turned out to be 2 volts, not the 6.3 volts I'd been told. Being a sceptical sort I'd worked my way up slowly on the heater voltage and found 2 volts gave a level emission and stable current. Phew!

The really worrying time was 'first picture'. I went to bed that night well pleased with the pictures, only to find the next morning that the front of the tube had fallen off! A contact at EEV (now E2V) kindly analysed the remains and told me that the tube was probably a badly made prototype, and the shock of being powered up after 50 years showed up the defect! These tubes are made of standard lab glassware and the front window is a large watch glass bonded to a lab cylinder. The EEV people also explained the 'ion burn' effect that I'd observed on the pictures. It's caused by atmospheric helium being drawn into the tube over decades of time (helium goes through glass). All tubes suck helium in but some mechanism (it was never clearly explained to me) causes the helium to produce a darkening of the image at the picture centre.

The camera was exhibited at IBC in Amsterdam. It all went very well - it worked fine for the whole of the show. The 'interesting' part was transporting the two tubes to Amsterdam by air as hand baggage. I really thought one would implode . . . Neither did, but I'm sure that I wouldn't be able to do that now!

The solid state electronics was designed to be multi-standard and the camera was demonstrated at 625/50, but runs with no modifications at 405/50 and 525/60. My new project, 'Project Vivat', a plan to create an early 1950s style Marconi OB truck by 2012 (see temporary website at www.projectvivat.co.uk, or CQ-TV 229 for a fuller article), might benefit from having a 'side show' of a 405/50 Photicon. Thus, I might be tempted to power the camera up again, this time on 405, but not until this time next year when my long term academic project will be complete (hopefully). For 'Vivat' we're looking for an early 50s Marconi vision mixer plus LCA (Line Clamp Amplifier). Most of the other bits of equipment are now sourced, including plenty of cameras, but this is a hot 'need'. Equipment for this has already come back from Australia, New Zealand and the USA, so distance is no object!

Best regards,

Paul M

PS There were some articles on this camera in CQ-TV, about 181/182, I think.

G'day Paul.

Fantastic you caught onto this post :) and shared your experiences in building this camera. I am a big fan of your photicon camera project as I am fascinated in knowing what kind of pictures these early camera tubes gave back in the day and am so pleased of your success in getting the photicon tube to work! :) I have been checking out the CQTV magazines and have found the two articles on your camera, was an excellent read!

I am also very excited hearing about your latest project Vivat you mentioned and will be following it as you give updates on the site. Looking forward to seeing it in action via the web :). It is going to be so awesome to see the classic OB unit up and going again. You might have heard in Australia an ABC camera technician/operator Barry Lambert revived a 1956 ABC OB van and the PYE cameras onboard http://www.abc.net.au/local/stories/...19/2340229.htm , totally amazing!!! :)

Anyways I was wondering if you have actually recorded any footage from your photicon camera to video or DVD when you had it in operation and if you have could I possibly purchase a DVD copy of the footage as I am so wanting to see how an ancient pre-IO tube pictures looked in fluid motion?

Lastly your photicon project has inspired me to want to build a working image orthicon camera using solid state electronics and I have started up on studying the technology and gathering resources. It's a long term project from what I foresee at this stage as my knowledge of electronics is currently at a basic level but I have strong intentions to make this project a success. So far I have imported a 50s General Electric GL-5820 3" IO tube which can be seen on my site on this page http://1970scountdown.atspace.com/orthicon.html and I have the tube data on that tube, plus I have downloaded from CQTV issues 89-91 1975 schematics and info on a home brew 4.5" IO tube camera which I believe will come in handy, though I am guessing modifications will be needed for it to drive a 3" IO tube. And my former work place build transformers and coils, so I'll get them to make the yokes. When I successfully build one, I will then probably get an enclosure custom build into the shape that is same or similar to that of a RCA TK-30/31.

Hello to our 'fellow travellers' in Oz!

Yes, I am aware of the sterling efforts of Barry Lambert - in fact this was one of the spurs to launch 'Vivat'. There is another complete Pye truck in Hungary (I've seen it), but it doesn't work, so it really is a very important piece of work. The Pye gear suffers from bad mains transformers and this has limited the number of working survivors in damper climes such as the UK, I guess that you don't have that problem! The Marconi kit is much more rugged in that respect. We are starting from a rather lower position, a wreck of a truck, incomplete equipment stock and no major benefactor. The other reason for starting this was the forthcoming Diamond Jubilee of HMQ, and the fact that Dicky Howett and myself have the only two surviving cameras out of the 21 used at the coronation in 1953. They are both cosmetically restored, having spent 25 years on a rubbish tip, but they can be taken to 'working' with a *bit* of effort. Attached is a picture of the latest piece of kit 'off the production line' for this project, a BD819A 405 line monitor. The tube is like new and the monitor (1952) is very sophisticated for its year having dynamic focus, regulated HT, regulated EHT, clamped frame scan and clamped video. It joins all the other bits of kit (including a working MkIII camera) that's destined for the truck. One of the other working monitors (not like the BD819A, the 'simpler' Marconi type from the early 1950s), came back from Australia some years ago. There's two more of that type yet to be repaired/restored too. Oh, and the latest 'hot' news is that we have new number plates (old style) for the truck itself (!).

Excellent news about your plans to build a solid state IO. I would humbly suggest that the most difficult problem will be in the scan/focus coils. You *could* copy an existing design of same with high voltage drive, using modern power FETs as valves (in effect), or, you could do as I did and go low voltage. This would need an existing design re-working, of course.

I do have some outside scenes recorded via the Photicon on VHS, but -

a) I don't know where the tape is!
b) It was 13 years ago and I don't think that the physical tape was new then!

I'm terrible at documenting things like this, so I'm fortunate to have my Golden Age TV oppo on board with 'Vivat' to do the business in this respect!.

Good luck with the camera, we need to stay in touch. I have the odd 'spare' IO yoke if it might help you, and access to original Marconi factory production drawings of things such as yokes too.

Cheers,

Paul M

G'day Paul. I've sent an email to your contact email address given on the Golden Age TV Recreations site in regards of the IO camera project and other things camera related, so keep a look out for an email coming from ac_dc_rocks@hotmail.com (my email address). I look forward to your reply.

Anyways that's one nicely restored monitor, very nice picture and looks cosmetically brand new, excellent restoration job!!!