[Boatanchors] TV-7 Tube Tester Noise Question

[whitebear1122 at comcast.net]

I was testing a 5V4 the other night.  I was suspicious of it because it came out of a Collins 32V-3 with a blown LV transformer.  The 5V4 was the LV B+ rectifier.  
The 5V4 yielded the proper reading when the RECTIFIER button was pressed.  When I ran through the SHORTS selection on the switch, all short positions caused the NOISE lamp to stay lit.  I thought AH HA, the tube is shorted.  I put in a NOS 5V4 and got the same reading and short response.
Now I"m wondering if the TV-7 SHORT circuits work with the 5V4 tube or do I simply have an old shorted tube and a NOS shorted tube....  
Have you guys tested rectifiers for shorts on the TV-7?
Thanks, Scott WA9WFA