[Amps] Titan 425 Reflected Power

[Jim Brown]

On Mon, 25 Sep 2006 07:22:53 -0700, Michael Tope wrote:

>Are you sure that you have done due diligence twiddling the
>amplifier load and tune controls with a zero reflected power 
>reading on the external Bird meter (higher VSWR reading on
>Titan meter). 

Thanks for all the ideas, both on and off list. I've got some work 
to do when I find some hours. One of the most interesting 
responses was this one from N7KA. The symptoms match mine exactly 
on both of the two Titans I own, and I also bought new tubes for 
the same reason he did. 

>I purchased a used 425 and experienced low output and if I 
>increased drive output might go up but grid current went way up.

>Here is what was found to be the problem.  The coasx going into
>and out of the input low pass filter board uses tho9se el-cheapo
>japanese connectors. found the center conductor of the miniture
>coax is used a "plug-in" pin into the pcb of he input filter.
>Guess over time corrosion got the best of it. I soldered both the
>input and output coax lines (center conductor) to the pc board
>and mhy problem went away:  1500W out without exceeding the max
>grid current.
> 
>I purchased a pair of new tubes, 3CPX800A7 tubes because I
>thought tubes were flat: NOPE.  Now I have spare set of tubes,
>NOT FOR SALE. 

73,

Jim Brown K9YC