[R-390] 26Z5's

[chuck.rippel at cox.net]

After trying a pair, the most elegant modification which eliminates the 
26Z5's is using the Sigmapert replacements.  Therre are many good 
reasons to remove the 26Z5 firebottles, most are covered in the R390A 
video.

I'm installing an owner procured set of the Sigmapert replacements in 
the present radio I'm working on and took the opportunity to read the 
theory of operation and design objectives.  He addresses the 
shortcomings of both the original tubes and their diode du jour 
replacements.  I'm going to strongly recommend the Sigmapert from here 
out.

A second item which, IMHO would benefit from being addressed is that of 
the lack of a "real" STANDBY" condition when the radio is set to that 
mode.  I thought I had a solution which was to pull a voltage from the 
antenna relay and use that to switch another relay which opened both B+ 
lines but that path is not to be.  The logic is such that the B+ is 
turned off when the radio is set to CALIBRATE.

There is mote likely another path; gotta look harder at the mode switch.


Chuck Rippel
--
"The democracy will cease to exist when you take away from those who are 
willing to work and give to those who would not."

-- Thomas Jefferson