Re: Tube condition

GregS wrote:
I think I asked this question before, but never got any
good answers. I was checking a bunch of Telefunken 12AX7's.
I got different, mostly improved readings on the 539C tester by
tapping on the tubes. What do I believe ?

greg

Chas E Miller mentioned "an old serviceman's trick", in his book on valve
radio repair, of tapping ECC85s with the handle of a screwdriver when they
wouldn't oscillate in FM front-ends.
I have found that it sometimes works, though I still replace them with new
anyway.
Martin.


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Relevant Pages

  • Re: Tube condition
    ... mostly improved readings on the 539C tester by tapping ... is the existing socket nice and clean with the ... Try tapping on the meter as well. ... If I did 10 tubes measured before and after, ...
    (rec.audio.tubes)
  • Re: Tube condition
    ... mostly improved readings on the 539C tester by tapping ... on the tubes. ... is the existing socket nice and clean with the ... Try tapping on the meter as well. ...
    (rec.audio.tubes)
  • Re: Tube condition
    ... GregS wrote: ... Good tubes are hard to kick to death. ... noise voltage I measure ... Buying NOS tubes can be very dissapointing!!!! ...
    (rec.audio.tubes)
  • Re: Identify frame steel
    ... Sometimes by tapping the tube with your fingernail you can detect where the butting begins on a tube. ... Seat tubes are usually single-butted, top tubes and down tubes are butted on each end. ... forks ends... ...
    (rec.bicycles.tech)
  • Re: Identify frame steel
    ... Sometimes by tapping the tube with your fingernail you can detect where ... the butting begins on a tube. ... Seat tubes are usually single-butted (at ...
    (rec.bicycles.tech)