Shorted Tube Question

[Davidg]

I was jumping in a couple of different caps to try in the tone stack of a traynor Ive been fooling with and the 2 100ohm filament ground res went up in flames=tube shorted confirmed with cont test. My question is there anything I could have done to cause or hasten this problem.Had just changed tone caps with jumper wires and was playing when the fireworks started-dont see how It could be related and how do u guys jumper in parts to try?could too long of jumper wires be a problem or just coincedence?

[HotBluePlates]

What was the tube that you found to be shorted? Did you confirm that short with the tube in the socket, or out of the socket?

[Davidg]

Tube out of socket, was a dead short had continuity from pin 2 to pin 3 on el34.I dont see how I could have caused it but I am no expert.It must have happened quick 2 because the shorted tube had most of the flashing burnt off of it, I was playing heard a hum and looked up and saw flames but I couldnt see the tubes -replaced the res and took tubes out and powered back up ok then that is when I found the short when I checked tubes with DMM.

[stratele52]

Your tube have internal short between plate ( pin 3 )  and heater  ( pin 2 ) . Very strange.

[darryl]

Your tube have internal short between plate ( pin 3 )  and heater  ( pin 2 ) . Very strange.

Sometimes there can be a flashover between pins 2 and 3 inside the valve base - where wires are passing out of the sealed glass and into the tops of the base pins. Once an arc has occurred, the carbonised track between pins 2 and 3 remains as a low resistance path. This can generally only be seen by breaking the valve base away from the glass bottle.

[Davidg]

I thought it to be strange as well, the first tube I have had short on me but most I have heard of was from filament to grid- thats why I wanted to make sure there was nothing I could have done to cause it.I was jumping a cap into normal channel tone stack on v1 and had not touched anything near the power section.I will chalk it up to coincidence and russian tubes!

[HotBluePlates]

... I wanted to make sure there was nothing I could have done to cause it. ... I will chalk it up to coincidence and russian tubes!

No, there's nothing you could have done in the tone circuit to cause an output tube to short.

And don't chalk it up to Russian tubes: I've only had one tube short, and that was a blackplate RCA 6L6GC.

[jim]

Hotplate is right but if you had the chassis upside down  (tubes down) and not supported by a cradle or chassis vice you could have damaged the output tube by loosening the glass or partially dislodging the tube from the socket.  Jim

[Davidg]

Thanks to everyone for taking time to reply.

Hotplate is right but if you had the chassis upside down  (tubes down) and not supported by a cradle or chassis vice you could have damaged the output tube by loosening the glass or partially dislodging the tube from the socket.  Jim

Amp is a Traynor ygl3 mk3-pretty cool design,the top of the combo comes off with four screws and there is everythingcaps and all so the chassis was still in the amp. It really was the perfect amp for me to start with because it is so easy to work on and try stuff-plus I have a 3 year old and I dont leave anything out of the chassis-if her and the wife go somewhere for a minute I can pop the top and be tweaking in about 30 sec.-Good advice though Jim Thank You