I have a 5U4GA that is intermittent on my tube tester. I believe that the loose base is causing this. I have a few ideas.
1. Throw it away
2. Use 5 min epoxy to keep it solid. Drizzle in some 5min around the glass and bas, wipe clean... let set. Reflow the pins after glue up.
3.Retest on tester and insure it is not intermittent.
PS Cyano glue did not hold
Whats your experience with loose bases.
5U4GA loose base
Moderators: pompeiisneaks, Colossal
Re: 5U4GA loose base
Throw it away.
-
Stevem
- Posts: 4618
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: 5U4GA loose base
Intermittent issues are not caused by a loose base, that condition though with enough time can lead to loss of vacuum however.
I have had many Octal base tubes over the years that have had a bad solder connection in one of the pins, if you have a hefty enough iron try reflowing them.
If that works then I find the loose base issue is best cured with a nice bead of black automotive silicone gasket maker spanning between the base and the bulb, in fact I have used this stuff to greatly reduce the micophonics in quite a few very expensive NOS output tubes that otherwise could not be used in a combo type amp.
In terms of throwing the tube away, if that tube in a dark room shows a blue glow, then yes toss it because it's only going to fail on you and probably at a time when you can least deal with it doing so!
I have had many Octal base tubes over the years that have had a bad solder connection in one of the pins, if you have a hefty enough iron try reflowing them.
If that works then I find the loose base issue is best cured with a nice bead of black automotive silicone gasket maker spanning between the base and the bulb, in fact I have used this stuff to greatly reduce the micophonics in quite a few very expensive NOS output tubes that otherwise could not be used in a combo type amp.
In terms of throwing the tube away, if that tube in a dark room shows a blue glow, then yes toss it because it's only going to fail on you and probably at a time when you can least deal with it doing so!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
-
Stevem
- Posts: 4618
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: 5U4GA loose base
This is how I apply a wide bead of gasket maker to negate a lot of microphonics.
You do not have the required permissions to view the files attached to this post.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
-
johnnyreece
- Posts: 997
- Joined: Thu Jan 26, 2012 2:05 am
- Location: New Castle, IN
-
Stevem
- Posts: 4618
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: 5U4GA loose base
If you have the right amperage mains fuse in your amp there is little risk of harm from a shorted recto tube.
It’s the repetitive fuse blowing of novice trouble shooting that can take its toll on the PT.
It’s the repetitive fuse blowing of novice trouble shooting that can take its toll on the PT.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: 5U4GA loose base
Thanks for the replies. I will do some repairs and see how it holds up.
Cheers Ange
Cheers Ange
Re: 5U4GA loose base
Used 5min epoxy and reflowed the pins. Seems ok.
You do not have the required permissions to view the files attached to this post.