[Amps] Fwd: Ten-Tec Titan 425 - input SWR high

Prem va3uma at gmail.com
Sun Oct 19 09:37:31 EDT 2014

Good morning gentlemen, and thanks to all for the quick and concise replies.

- One of the tubes being bad: Will see if spares are available
- LPF caps going bad: My plan was to analyze the cut-off freq for each band
(@ Z=50R) on my Spec-analyzer/tracking-gen - but left this option to the
last, and also wanted to hear of other 'easy' methods from the gurus who've
already worked on this Amp.
- Plate/Load settings: The actual numbers match the ones in the manual
(surprisingly - even after all these years).


---------- Forwarded message ----------
From: Prem <va3uma at gmail.com>
Date: Sun, Oct 19, 2014 at 9:24 AM
Subject: Re: [Amps] Ten-Tec Titan 425 - input SWR high
To: wl7e at arrl.net

Roger that, Joe. Will let you know.


On Sun, Oct 19, 2014 at 9:12 AM, Joe <wl7e at arrl.net> wrote:

> Prem,
> I would be interested in what you find out. I am having the same trouble.
> I am now replacing the tubes in my Alpha as that seems to be the culprit.
> 73,
> Joe WL7E
> On Sun, Oct 19, 2014 at 5:02 AM, Prem <va3uma at gmail.com> wrote:
>> Friends, for a long time now, the input SWR on my friend's Ten-Tec Titan
>> 425 is very high (average > 2 on all bands) - when measured with a MFJ
>> analyzer at the input - with a 50R dummy-load at the AMP output.
>> So long, he's used an ATU between the exciter and the 425, but I'd like to
>> find out if there's way to fix this SWR problem (no slug-tuning. fixed L
>> and C in the i/p LPF).
>> I've already checked/assessed the following:
>> 1- Amp gives full o/p of 1500W pep on a DL with an ATU between the exciter
>> and the amp (so, tubes should be OK ?)
>> 2 - The vacuum relay contacts test 100% OK with a multi-meter continuity
>> test.
>> 3 - No visual or smell indication of any burns/arcing/toast - in the I/P
>> LPF or in any other circuit elements.
>> 4 - Band switch contacts look good. Cleaned with De-Oxit - just to be on
>> the safer side.
>> 5 - Ig and Ip are as per specs
>> Any help/lead is appreciated.
>> 73,
>> Prem
>> www.qsl.net/va3uma
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