Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: richie60 on February 03, 2019, 07:58:04 AM

Title: Can a tube just go bad with no warning?
Post by: richie60 on February 03, 2019, 07:58:04 AM
Unplugged my amp and gently placed it on another table to give the cabinet a clean today.  When I connected it back up, although the tubes glowed, there was no sound at all.  When doing the voltage checks on the speedball I noticed that the led's weren't lit on the large board.

This had me worried and was scratching my head thinking what could have possibly gone wrong just moving my amp?  Left it for a few hours and came back to it later, I had the stock tube 6080 so I put that in, did voltage checks, all passed and the led's all lit.

Can't understand how my NOS 6080 Thompson tube could just fail like that.
Title: Re: Can a tube just go bad with no warning?
Post by: Doc B. on February 03, 2019, 09:04:07 AM
#1 reason for this is a bad solder joint. #1 cure is reflow your solder joints. Start at the 6080 socket.
Title: Re: Can a tube just go bad with no warning?
Post by: richie60 on February 03, 2019, 09:51:54 AM
Ok thanks.  Solder joints looks good but will reflow to be sure. 
Title: Re: Can a tube just go bad with no warning?
Post by: richie60 on February 05, 2019, 07:00:08 AM
Well I've been using the amp without any issues with a different tube, so I'm going with my original theory that the Thomson valve just gave up the ghost.  Soldering looks just fine to me.