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.