You may want something to monitor the current draw as you bring it up.
Also keep the intensity low in case the timebase decides not to run to avoid screen burn.
Found a older version of the 383 large screen oscilloscope from Airmec (taken over by Racal) here;
https://www.bidspotter.co.uk/en-gb/a...3-a8e9010e6f33
And another older Airmec large screen scope here;
https://www.***********/photos/anachr...7624562074349/
WME_Bill mentions he has a manual for the Airmec 279 here (post 6);
https://www.vintage-radio.net/forum/...ad.php?t=55842
No idea how much difference there will be in all these older models.
David