Too bad sorry to hear this. Leave it to the idiots that want things different then having a standard polarity having positive center pin and negative outer conductor. I always refer to these CRT's ."lollypop tubes".I got to sets here.
I dont know what model number you have .I found these service manuals online.
http://freeservicemanuals.info/en/se...None/WATCHMAN/
https://www.manualslib.com/manual/10...page=12#manual
https://www.manualslib.com/manual/85...-Fdl-250t.html
http://hackaday.com/2011/10/03/hack-a-watchman/
Where it says service manual.Click it for the service manual.