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Re: [Amps] High grid current Titan 425

To: <amps@contesting.com>
Subject: Re: [Amps] High grid current Titan 425
From: "Dave Hachadorian" <k6ll@arrl.net>
Reply-to: Dave Hachadorian <k6ll@arrl.net>
Date: Fri, 26 Oct 2012 21:01:38 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I don't know beans about the Titan 425, but isn't there a glitch diode, or a grid metering resistor, which, if they blow, cause cathode current to show up as grid current on the meter? This rings a bell on my AL-1500, but I don't have time to research it now.


Dave Hachadorian, K6LL
Yuma, Arizona



-----Original Message----- From: Rich Hallman - N7TR
Sent: Friday, October 26, 2012 8:49 PM
To: amp reflector
Subject: Re: [Amps] High grid current Titan 425

Did a bit more testing. I pulled both tubes and replaced with a known good 3cx800a7. Im seeing the same problem, and looks like I get max grid current just by enabling the T/R circuit on the amp with no RF drive. Confirmed I have HV on the tubes. I pulled the access cover off under the case to see the bottom of the tubes. Nothing stood out as being blown.

Thoughts?

Thanks..

-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Rich Hallman - N7TR
Sent: Friday, October 26, 2012 6:30 AM
To: amp reflector
Subject: [Amps] High grid current Titan 425

I just had an arc happen on my Titan 425 this morning that blew the fuses in the PS. When I replaced them I had high voltage to the RF deck, but I'm seeing high grid current now with just 20 or so watts of drive. Output is very low.....less then 100 watts. Do I have an issue with the tubes? Thoughts?

Thanks.   Rich.  N7TR
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