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I'm working on a 40-195 and have recapped, checked resistors. The radio is the run with a 6J8 in place of the locktal tube. The radio comes on and tunes now, picks up lots of stations however the sound is crackly and warbly. The 7G7 (repl for 1232) locktal will make a little noise when it is manipulated in the socket. Is there a remedy for this? Don't know if this tube maybe the culprit as it tests fine with no shorts. All other tubes tested fine as well. The 42's tested a little low but they do as a rule I was told many years ago. Any help that can be offered would be greatly appreciated!
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Does it only makes the crackling sound when you touch the 7G7 tube? A crackly sound usually indicates an intermittent connection somewhere. I keep a plastic stick for when I have a problem like this. I will lightly tap on each component until I find the culprit.
(This post was last modified: 11-24-2014, 09:37 AM by
Jeremy S.)
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I had to re-read your post again. Here are a few ideas that I have:
Cold solder joint: Might try reheating each solder joint and making sure that the solder flows and bonds well.
Loctal socket: This sockets are notorious for having bad connections with the pins of the tubes. I have fixed them before by using a small pick or screwdriver to slightly bend the tube pin contacts for a tighter fit.
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Does it make the noise just after turning on the set say for 5 minutes or still making noise after 30 minutes? Like other have said cold solder joint sometimes using Deoxit on Q-tip clean all parts of tube sockets and base of all tubes. Dampness can also be a problem that will go away after about 30-45 minutes. David
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(11-24-2014, 12:56 PM)Jeremy S Wrote: I had to re-read your post again. Here are a few ideas that I have:
Cold solder joint: Might try reheating each solder joint and making sure that the solder flows and bonds well.
Loctal socket: This sockets are notorious for having bad connections with the pins of the tubes. I have fixed them before by using a small pick or screwdriver to slightly bend the tube pin contacts for a tighter fit.
Your recommendations are good ones I will follow! Those locktal tube sockets have openings almost like eyelets; I'll try your method. Thanks!
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(11-25-2014, 02:29 PM)David Wrote: Does it make the noise just after turning on the set say for 5 minutes or still making noise after 30 minutes? Like other have said cold solder joint sometimes using Deoxit on Q-tip clean all parts of tube sockets and base of all tubes. Dampness can also be a problem that will go away after about 30-45 minutes. David
It's continuous. Highs are tinny, warbly. Bass cuts in and out. When you wiggle the 7G7 it seems to try to change the sound quality.
