Motorola TS-95 chassis odd discovery - any ideas?

[kramden66]

I was getting ready to work on this chassis when i noticed at the rear the tube line up from left to right is supposed to be 6SN7 , 6AL5 and 6BQ5 , the 5u4 on top of the transformer , i looked at my chassis and where the 6AL5 should be is a big tube , i thought is that another 6SN7 ? even if it was it wouldn't fit a 6AL5 socket , so i pulled it and it has dark sides with only a little on the top visable , it has odd numbers almost like a glass ballast tube , anyone know of any alterations like this ?
the tube chart , the service manual and the sams all show 6AL5 , if anyone knows what this is about please let us know , i can put up the numbers/letters on it when i have a chance to look at it again.
mike