The Heart Of The Magnetic Field Problems For CBS Studio 50
The Heart Of The Magnetic Field Problems For CBS Studio 50
In one of today’s earlier post about CBS ordering the Maconi Mark VII color cameras, I mentioned the the legendary magnetic field problems they had in Studio 50 and also, Studio 52.
Circled in red is the heart of the problem. That’s where the massive transformers for the subway were located. This is on 53rd Street with Broadway being just up at the corner on your right. The dark building to the right of the transformer building is the stage of The Ed Sullivan Theater (Studio 50) where David Letterman is done.
The building on the left is the rear of what was once CBS Studio 52, with the front entrance on 54th Street. After CBS sold it, it became the famous nightclub “Studio 54”.
Even in the Black and White days, cameras had to have special mumetal shielding inside to block the interference. Jackie Gleason once hired an RCA color truck with TK41s for a test of the show in color in the early 60s, but no matter what they did or where they parked the truck, they could not get a good picture. Enjoy and share! -Bobby Ellerbee
the thing u never new till Bobby told you !! love it !
Faraday cages!
In the days of tube monitors on mobile units, trucks at MSG had the same issue
AC Traction Motors which create huge magnetic fields. Every time a train started up on track 20 or 21 from the LIRR, the signal on the monitor would look like it was being degaussed
Mc Giver it Matt, lol ( ok, a mis-spell )
In one of the remote trucks I helped build we had some Panasonic monitors that were all next to each other in the home made wooden rack. The cases were plastic and sync bars from one would effect the picture on the others. The solution was to wrap them in aluminum foil, cover that in gaffers tape and cut holes for the vents.
Great story and great responses!
Fascinating stories guys. Tesla is having a field day with this post, no doubt. I learned early on in TV repair that mu shielding was important to be refitted after tube replacement with the chassis transformers back in the day would affect color convergence alignments, besides xray emissions off the back. Proves what you can’t see can hurt you, in one way or another.
On the last daytime “To Tell the Truth” in 1968, Bud Collyer mentioned having issues with the cameras. I think they taped in 52; I wonder if this was what he was talking about.
Just to clarify your comments on the magnetic field problems. I was the Norelco Project Engineer responsible for developing a PC-70 Camera that would operate in ST 50’s Magnetic Field. The building in question in your post housed three large DC generators not transformers. To compound the problem, the very large output cables of these generators were hung on the common wall of that generating station and the rear wall of St 50’s Stage. In addition to the cameras in St 50, all the monitors in the control room required mu-metal shielding. The first color cameras used in St 50 were specially shielded Norelco Plumbicon’s. These cameras were designated as PC-71 cameras and these preceeded the Marconi Mark VII’s. Shortly after the PC-71 Installation, CBS Engineering offered me a Project Engineer position which I accepted. I retired from CBS 29 years later. About the time the Marconi’s were installed, The NY Transit Authority removed the DC Generators and replaced them with AC Generators which did not generate the same offending magnetic fields in the adjacent St 50. That generating station is no longer a primary power source. It is a back-up system for the Transit Authority. When CBS was rebuilding St 50 for the David Letterman Show, I was asked to investigate whether there was any existing magnetic field problem. I did so and found that no magnetic shielding was required for the cameras and monitors in the new St 50.
Reminds me of when UVA got a magnetic imaging machine and their video department tried to shoot video of if going into operation…with tube-type cameras! I thought I would never get their registration back again!
In a former life I investigated a similar issue in Toronto. The complainant was in an office on the second floor facing a street with streetcars. Underground was a subway line. Every time a subway would accelerate out of the station below, his computer display would pull and tear. Turns out he had the 600VDC feeders common to the streetcar and subway on poles right outside his window. An accelerating train could draw a couple thousand Amps, and it pulled from the DC grid any which way….A CRT is a sensitive Gauss meter.
This is still an issue. We were shooting the PBS series “Sound Stage” at the Roseland Ballroom right across the street from Letterman and found that all the cabeling had to be flown into the building because of the interference crossing the sidewalk. this was just the last couple of years.
Could not use a pro camera to get video of an MRI machine after the magnets were first energized. Sort of the same problem. I was a hospital medical photograpgher.
I take it since after the 60’s, Engineers had been able to reduce the interference in the building?
And you could hear the sound of the rotors at the back of the Studio 50 stage. (I was never inside 52.)