[R-390] 26Z5W Failure

[David C. Hallam]

I have had one of the 26Z5 rectifiers go out without out affecting the other
one.  Don't know how long this situation went on as I only found it when I
took the radio down for a complete alignment.  Mine is a R-390 nonA.  I had
spares and installed them so the alignment could go ahead.  However, upon
looking at the replacement cost of a pair of 26Z5's, I purchased a pair of
Copper Top replacement solid state 26Z5's from Weber's.  Quite frankly, I
purchased my R-390 years ago and a pair of new 26Z5's were about the same
price I paid for the radio.

When I received them, I removed the vacuum tubes and installed the SS
devices.  There was no change the B+ after the SS device installation.

David C. Hallam
KC2JD

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]On
Behalf Of Gene Dathe
Sent: Monday, February 21, 2005 12:09 PM
To: r-390 at mailman.qth.net
Subject: [R-390] 26Z5W Failure

Steve wrote:

It is possible to loose one 26z5 at an earlier time and the radio operate
normally. Each tube has two cathodes and two plates (four plates and four
cathodes total). Both high tension leads from the power transformer are
shared by each tube. If one tube goes dead, there is still full wave
rectification.
...73..Steve...N8YE

Yikes, that's not the radio I have..!  The plates of each tube are connected
in parallel (pins 1 and 6).  Each tube is connected separately to either
side of the center-tapped secondary.  So each tube is a half-wave rectifier,
fed through L601 and fiter cap C606A.  Lose one tube and you have a half
wave rectifier...

The responses I have gotten (Thanks, all,) seem to indicate that both tubes
go at once.  Anyone blow just one? Or just too much current in the remaining
tube?
73 de NA0G  Gene


_____________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/faq.htm
Post: mailto:R-390 at mailman.qth.net
Unsubscribe: http://mailman.qth.net/mailman/options/r-390