[R-390] R-390A.... 12BA6 in PTO and BFO

[David C. Hallam]

Unless you are operating with extreme temperature variations or mobile, 
I don't believe you will detect any difference.  I used them for years 
in my R-390.

David
KW4DH

On 11/11/2014 11:47 PM, Pete Williams wrote:
> ​    Probably been mentioned, but 12 BA6 can be used in PTO  and  BFO while
> waiting for a replacement ballast tube.
> Jumper pins  2  and 7 on the  3TF7.
> You have to replace both of  course  as the heaters  are  series from the
> 25 V  supply .  I only noticed this  on a PTO being checked out.
> Stability /performance not  checked .
> Cheers
> Pete V K3IZ
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