Museum of the Broadcast Television Camera

E-mail Received, 31 January 2010

Marconi MkI TV camera

Hello Brian,

I followed a link to your TV Camera Museum. I was knocked out to see the Marconi Mk1 camera that I had owned back in the seventies. It is with mixed feelings that I write to you, as the reason that I am certain that the camera was once mine is that I am afraid I was responsible for painting parts of it black! Learning that there were only ever six of these produced only heightens my sense of shame.

In my defence I did rescue the camera its CCU and PSU from an infamous scrapper of any equipment that contained large transformers. I was only fourteen years old at the time and had a lot to learn about valve electronics and the art of sympathetic restoration.

The camera was missing various parts when I acquired it chiefly a control cable plug and socket and a couple of cooling fans. It had no lenses apart from a pathetic specimen mounted on a lashed in C mount. It did come with a manual though. At the time there was no great interest in keeping 405 TV Alive that I had noticed and so I wrote to Marconi who were good enough to supply me with 625 line standard circuit diagrams. Of course the sensible approach would have been to get the thing running on 405 lines first but I pitched in and started changing resistor values instead. Ultimately I had neither the know how or the test gear and the project was too complex for me.

Thinking back I am surprised how many specifics I can remember about it; I seem to remember the manual showed the IO alignment coils as being mounted on a rotatable section of the yoke. On this camera though they were fixed and some additional controls were 'fitted' to the CCU instead. The other point which sticks in my mind is that I always thought that it was intended for OB use. I can't remember if I was told this by the previous owner or whether it was mentioned in my covering letter from Marconi. There was a mains voltage selector control on the front of the PSU that had no specific voltages marked, it was just increased until the meter reading was on its mark. I feel that this might support the case for it being an OB camera, not on the public supply and fed from a cable of indeterminable voltage drop and so on.

It is great to see it again and I wish you every success with the museum. In the unlikely event that you think I might be able to resolve any questions about it I would be more than happy to assist.

Best wishes
Charlie Watkins.




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