The 5U4 was in the socket when I got the set; I have a correct 5V4 that I will install after the chassis work.
The picture with the same fuse I have is from an 8TS30 that Steve Pielock restored and described on the Antique Radios forum. Here is the picture link:
http://i249.photobucket.com/albums/g...CIMG6905-1.jpg
I hope the flyback has not already been damaged from having that 5U4 in there...