Vision mixer type 261 - what does "Emergency" do?

[Stockden]

For reasons best know to it's algorithm Amazon video suggested I watch "A Hard Days Night" recently. It must be over 45 years since I last saw that film so, ever a sucker for nostalgia, I had a look.

Perhaps unsurprisingly (and despite not having a broadcast or video background) I found myself paying much more attention to the TV studio scenes and equipment than I ever would have done as a teenager. One of the things that caught my eye was the prominent "Emergency" bar at the top of the EMI type 261 vision mixer that was visible in several shots.

So, purely out of curiosity, what did that do? Was it a common feature of vision mixers at the time and is it so today?

[PaulM]

The 'emergency' is failure of major video systems.
It's a simple cut bus between sources which bypasses anything in the mixer which is complicated and has gone wrong.

A normal feature at the time, although designs varied, but it was often just a bunch of relays (or simple switches) hard switching the incoming video which may go right back to the sources (cameras etc.) taking out another level of possible trouble in distribution amplifiers and sub-systems.

Nothing complicated or sinister - just a fix in case of electronic and/or wiring failure to 'keep the show on the road'.

The one in the picture is under a lift-up flap to prevent accidental operation.

Not really needed today and difficult to do in a software controlled environment, but I think it's usually still an option (of sorts).

Best regards,

Paul M

[Stockden]

Thanks Paul. I suspected that the emergency in question would be an equipment failure (rather than, say, a fire in the studio) but it's nice to know exactly what it did.

Hugh