[Johnson] Re: DO NOT Solid State the Power Supply in yourRanger!!

[Jerry K]

First, I'd flip the fan over. Secondly, maybe take a look at how you are
tuning up, what kind of loads are on the rig, how hard you drive it, and how
fast you can efficiently tune it. Also, check careful the value of cathode
and screen resistors in the PA. 6JB6's are not "key-down" CCS-rated tubes,
and were never intended to be. Depending on how the rig is used, and even
more importantly, how often and how quickly retunes are done and what kind
of load it's run into, 18 months might be a good service life. For the way
my particular TR-4 gets used (twice weekly nets, good antenna match, always
used on the same freq/band, gently driven, almost never retuned), 18 years
is probably more like it!  :-)
73, Jerry W5KP


-----Original Message-----
From: johnson-bounces at mailman.qth.net
[mailto:johnson-bounces at mailman.qth.net]On Behalf Of Sherrill Watkins
Sent: Tuesday, October 19, 2004 1:01 PM
To: Larry Knapp; Johnson at Mailman. Qth. Net
Subject: RE: [Johnson] Re: DO NOT Solid State the Power Supply in
yourRanger!!


Larry: My experience has shown that my Drake TR-4C will begin to damage some
of its tubes in about 18 months even with a cooling fan mounted over the top
of the cabinet above the final amplifier cage. The fan is blowing up. Do you
have specific information about how to correct this? If so, please share it
with me. Thank's  - Sherrill W. k4own.

-----Original Message-----
From: Larry Knapp [mailto:kc8jx at yahoo.com]
Sent: Tuesday, October 19, 2004 1:31 PM
To: Johnson at Mailman. Qth. Net
Subject: Re: [Johnson] Re: DO NOT Solid State the Power Supply in
yourRanger!!


I have to agree with Glen here.  There are most likely thousands of solid
state power supplies in use for Heath, Drake and Collins....most likely
others.  The Heath and Drake transmitters do not come with fans.  In all the
Drake forums a constant is to get the Drake transceivers and transmitters
fans to cool them down.  I would believe it's the heat coming from the
6JB6's
that perhaps may cause failure over time in these units...be they tubes or
components.  My R4B can run hours with what I consider normal heat from the
components used.
However, when I use my TR4CW or my T4XB, the heat from these units is huge.
Fans are on both.  I hope this prolongs their life.

73, Larry KC8JX

--- Glen Zook <gzook at yahoo.com> wrote:

As for the problems with your TR-4C tubes, frankly, I have never run into
such in either my equipment or the equipment that I service for others.  I
have worked on various Drake 4-Line equipment that belong to locals that
still have a number of the original tubes in them and have never had to
replace a single tube in any of that equipment.  Thus I cannot recommend
anything that may be wrong in your particular power supply.  But, I have not
seen the problem in any solid-state supplies in either my own equipment or
in
the numerous units that have been sent in for alignment, etc., over the
years.

Glen, K9STH

> --- Sherrill Watkins
> <Sherrill.Watkins at dgs.virginia.gov> wrote:

My Drake TR-4C will damage some of its tubes in about 18 months; based about
two or three on-off cycles per day. I have quit using it because of its
tendency to damage tubes so quickly. I plan to install a time-delay relay in
the center tap groud of the power supply to allow the filiments to warm
properly before the B+ is applied before I use it again. My high AC line
voltage (125vac!) doesent help matters.





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