[R-390] Role of the 3TF7 in PTO frequency changes

[Cecil Acuff]

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It has (been) shown by Dallas and me that voltage regulation is the better
alternative to achieve constant VFO frequency when power line voltage
changes.

Now a comment to the replacement of original parts with new ones. I
would e.g. NEVER replace original capacitors with orange drops. In my
eyes they are oversized and look unaesthetically (the orange drop
lovers will kill me). If possible I'd avoid any soldering in the
radio. That was the 'ultima ratio' when designing the 3TF7
replacement. But if a replacement (even a solid state device, Hallo
Heinz Breuer) fits well into the look of the radio I see no problem to
install it. The 3TF7 replacement with the medium size IERC tube shield
installed (http://schmid-mainz.de/Flyer.pdf) to my feeling isn't
recognized as a foreign body even by the purist.

As I stated above I'd never tolerate to do any soldering in the radio.
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True to form Lankford fan....

Dallas wasn't the first to look at voltage regulation.  If you go back far 
enough in the archives and also check the Chuck Ripple pages you will find 
him building a solid state voltage regulated replacement many years ago.

You will also find Lankfords last stand on cap failures and their direct 
lineage to the blue striper pile which don't hold water.  He has gone as far 
as to boil some on the stove, and then freezing them in his analytical 
testing to prove that as the cause and posted the results on the site he now 
frequents.

Sorry but I'm not a big follower..

Cecil
K5DL