Now I am getting confused, the MW36-44 is still down as being magnetic focusing on the data sheet, but I did look at it and wonder if that would also be an alternative to my tube in the 991T, so I have just done a look though some service sheets for the 991T and it says that the MW36-44 was also fitted to this set with the addition of an external wire link between pin 7 and cathode. So a quick dash to my set, take the back off again and check the valve base, low and behold the pins are already wired
The only thing is it does not have a top cap anode as indicated in the data, perhaps this is really an addition to the contact on the side? or there could be a simple adaptor?
I love all this information, it just brings more questions.
Adrian