There was an article from a ham in Texas on the internet on modifying the
425 for 3CPX800's but I can't find it. I recall it required an entire new
supply, including a custom-built Hypersil transformer from Peter W. Dahl
that ran more voltage and current than the original and fit in the power
supply cabinet. With the higher plate voltage, less drive was required, and
lower grid current for legal power, but I think the real object was to run
much more than legal power. The author claimed he tested the modified amp
at 3.2 kW PEP out..."on a dummy load of course" (yeah, right!). I guess
everything's bigger in Texas!
Like one Texan told me: "Go big or stay home"....
----- Original Message -----
From: "Jim Brown" <firstname.lastname@example.org>
Sent: Friday, December 03, 2010 1:04 PM
Subject: Re: [TenTec] TITAN 425 PS maintenance
> One thing you would need to consider is what other high voltage
> capacitors are in the RF deck that might need to be replaced with parts
> rated for higher voltage.
> As I understand it, the main reason for using higher voltage with 3CPX
> tubes is that you can achieve legal power with less plate current. I
> don't know if there would be reduced drive requirement, or less grid
> current. Since the primary failure mechanism in these tubes is excessive
> grid current, that's what I would pay the most attention to.
> Also, I don't know what's in this board, but to get higher voltage, you
> would probably have to replace the power transformer as well.
> The only condition under which I would look at this board as a
> replacement is if most of the power supply went up in smoke. :)
> 73, Jim K9YC
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