Pulling Power Tubes To Find The Bad One

[louderock]

Marshall Jubilee 100 watt. Blowing fuses. I suspect that one of the power tubes is bad. So, I understand that I should pull the power tubes and replace them one by one to figure out if one of them causes the fuse to blow. Question is, do I need to completely power off the amp before replacing each tube?

 

[wsaraceni]

i always power off my amp when replacing a tube. not sure if it will hurt the amp either way, but i personally dont want to crack a tube and touch the metal bits inside when its on.

 

[TweeDLX]

Think of it this way... You probably put the amp on standby when you turn it on, right? Why? So that the power tubes aren't subjected to the full power when they're cold. Plugging in a tube with the power on is like not using standby to warm up the tube. Just a few minutes of your life will increase the life of your tubes.

Mike

 

[louderock]

Well that makes perfect sense. I turn it off.

 

[rockon1]

I swap out my tubes on standby all the time. Bob

 

[mooreamps]

I don't have to swap tubes. The little bite led tells me which tube is bad.

-g

 

[Blue Strat]

I don't have to swap tubes. The little bite led tells me which tube is bad.

-g

...and this helps the OP, how?

 

[Structo]

You can do it by switching it into standby. That way only the filament voltage is present.
Be careful, output tubes get very hot!

 

[louderock]

I switched out tubes one by one (with the power off). The last one popped the fuse. I replaced the fuse and changed out the tube. All good now. It's working fine. I'm an amp tech now!!!

 

[Rosewood]

I switched out tubes one by one (with the power off). The last one popped the fuse. I replaced the fuse and changed out the tube. All good now. It's working fine. I'm an amp tech now!!!

Careful, you'll be buying scopes and meters now that you are tech.

 

[Structo]

What's your bench rate? lol

 

[louderock]

What's your bench rate? lol

2 Budweisers and a slice of pizza