Fender Bassman 10 heater issue

[lo-watt]

Got a strange issue: Had a Bassman 10 from 81 with a loud hum. Removed the Hum Balance pot,redid the heater wires to the two preamp tubes and tied two 100Ohm resistors to ground from each leg of the pilot light(6.3v). No issues..yet. Played through the amp loudly. Amp was pretty loud. About 10 minutes in amp blew the mains fuse. One of the 100 hm resistors smoked. Checked all the tube sockets for any bad solder joints or shorts. All new tubes installed. Disconnected the trans wires to test 6.3v out of circuit. Measured 6.8vac figured that was god with no load. Then i measured one side to ground and got 70VAC???

Am i missing something?(Highly possble).

[lo-watt]

Found a short between pin 2 to pin 3 on V5(left hand 6l6). Seems that would be an issue! Eyes are getting old. Shoulve seen that earlier.

[drewl]

Tube pins shorted?
That happens.

Check the socket for any burn marks or burnt carbon to be sure.

[lo-watt]

Just finishing up swapping out a new socket. Will fire it up in a sec. We all know those 80's Fenders were poorly wired.

[Enzo]

Um, it worked for 30 years, I think the wiring was OK. What probably happened was a power tube shorted, caused an arc across the tube socket between pin 3 and the closest shot to ground through the heaters on pin 2. That is likely why the hum pot burnt up. The 100 ohm resistor burnt for the same reason, then you replaced the power tubes.

[lo-watt]

Nope. Original Fender Labeled GEs are still good. Tested them on my MaxiMatcher. Pin 2 was physically touching the pin 3. Swapped sockets;all is well. Played full throttle into my 500 watt test vab no issues. Missed that the first time.