[R-390] maintenance

[Scott Bauer]

 Don,

 That is my reason for writing. To get the opinion of others. I have 
read of people running
radios 10 years on a set of tubes. Some do make good common sense. For 
example,
1/2 of some of the 12AU7's are gone.  Measuring 20 on 1 side and 90 on 
the other
 I am using the black IERC shields.
 I just had a guy here in Frederick, Bill Waters go through the testers. 
I have a 3rd that
was done by Chris Haedt.

 Thanks for your input Don. Have a good day!

 Scott W3CV


2002tii wrote:
> SCott wrote:
>
>> As I was testing the R390
>> tubes, I noticed one radio that needed an incredible 22 tubes.  These 
>> were all
>> fine last year. The radio ran fine with all the bad ( really bad ) 
>> installed. Thats amazing.
>> I decided I had better get out my spare tester, a Heath TT1-A to 
>> verify the condition
>> of the tubes and my TV7 All 22 tubes were just totally dead.
>
> Very odd.  So odd, I'd be more inclined to think you have two 
> erroneous tube testers.  The 390 beats on some of its tubes, but the 
> RF and IF tubes (for example) should run 24/7 for a large part of a 
> century without any sign of low emission or transconductance, even 
> with poor ventilation.
>
> Best regards,
>
> Don
>
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