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Old 10-22-2013, 05:13 PM
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holmesuser01 holmesuser01 is offline
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Join Date: Jul 2005
Location: Asheville NC
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Quote:
Originally Posted by Jeffhs View Post
Tube substitutions must never be done haphazardly. Putting tubes in the wrong sockets in a TV, radio or any kind of electronic equipment using vacuum tubes can have disastrous results; for example, the filament pins of one tube may well be the plate terminals of another, possibly causing circuit damage or worse (including but not limited to fire) if two or more tubes are put into incorrect sockets. I would never substitute one tube type for another unless I was absolutely certain the substitution would work. A good rule of thumb is to check a tube substitution manual if you are in doubt as to whether a particular substitute will operate properly. If you do not have such a manual, replace the tube with the same type already in the device you are servicing.
What he says.

Be absolutely sure that the tubes are in the right sockets before you do anything. I learned the hard way when I was checking out a set that used the 6DT6, 6AU6, 6AQ5 audio board. I was told the sound was fine, then nothing. Someone had switched the positions of the 6DT6 and the 6AU6, and I didn't look at the actual numbers. These tubes look similar, but are not the same.

I'm so glad that I have only one set that uses one 6GH8 tube. I never have good service from them, and they have caused more repeat trouble than I care to mention.
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