[morzh]

And it is 50/50 chance the fuse will still blow.

Eric

you gotta learn how to measure things or you will get quickly frustrated and give up.

The easiest way to check the tube, very basic, is buzz between the

1) Between pins 4 and 2, and then 4 and 3. There should be a clean open, NO conductivity whatsoever. Discard if there is any.
2) Between 1 and 4, and then 5 and 4. Same as above.
3) Between pins 1 and 5. There should be some measurable resistance in Ohms. If open, discard.

In case 1 or 2 are bd, there is a good chance this is your problem with the fuse.


http://www.radiomuseum.org/tubes/tube_84.html