Thanks a lot for this document Hakan, didn't know about this problem !
As it happens I just got a 2215 the other day, working on it as we speak... just checked, it's smack in the middle of the affected S/N range (mine is #20521), and it appears not to have been moded : no sticker at the back, and the transformer looks stock : still in revision -00 and the wire has not been unwound by one turn.
So my CRT / filament is cooked then, by now, after nearly 40 years of use... oh well... not much I can do about it, but at least if I find the trace too dim at fast sweep speeds (haven't checked specifically for that yet), I will know why and won't waste trying to "fix"/troubleshoot something that just can't be cured ! :-(
Vincent Trouilliez
Vince