Herbert : HELP. One tube doesn't light up anymore

Bourreau

Member
I got:

KT88 - 6L6 - 6L6 - 6L6 - 6L6 - KT88


The second KT88 doesn't light up anymore.

If I invert both KT88, the tube which was off, lights up!
And the one which lit up in the first socket, is off.

So I suppose the problem comes from the socket...
and not from the tube...

What can I do? :(

Thank you!
 
Seems to light up again when I move the tube from the socket...

and then, it doesn't light up when I try to power the amp again :?

Could it be a kind of a "poor contact" (don't know how to say it in English...) between the tube and the socket?
 
I'd check to see if you have any bent or broken contacts in the socket first, just start with whats easiest. If ya got a bent one, re-tension the contact. You usually want to go in and re-tension all of your tube sockets' contacts once in a while anyway to insure good contact to the pins, it can also help keep hum and other noises down. Its easiest to do this with a dental pick. Have you replaced the tubes alot/try alot of different tubes? If its not that then I don't know what it is.


Edit: get some contact cleaner like De-Oxit and put some on the pins of a tube and gently work the tube in and out in a circular motion, before you re-tension the sockets, to make sure they are clean.


Edit 2.0-also what brand of kt88? I've heard of the JJ tubes having smaller pins then normal, but I think that been fixed, not sure just another thought.
 
Thank you!

Now that I read that, I will dare to do it! :)

I haven't tried many tubes... None, actually... I got my Herbert with 2 KT88... directly from the store.
I wouldn't dare anything without asking... hehe, I'm a DIY catastrophe.

Hehehehe, with a dental pick, ok! This is the only link between my profession and my passion.
I prefer to use dental floss, less aggressive for gums, but in this case, I'll find some dental picks ;)

Thank you again... I'll tell you what.
 
Hehe, it now seems to work each time I power my amp!

The KT88 tube on this socket seems a very very little less luminous than the other KT88...
But maybe it was already like that before...

Now, this tube stays firmly in its socket.
It used to get out of its socket by itself before I re-tensioned the pins, thanks to your advice...

Damn! You rule, Nick ;)

THANK YOU VERY MUCH, once again!
 
Your very welcome! Glad to hear it worked out. :) That sounds normal about the not glowing as bright, some of the "glow-y" material doesn't poke out as much on some tubes.
 
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