[Elecraft] K3 Power Shutdown

[Joe Subich, W4TV]

 > Have you checked what your PSU is doing when you try to tx at more
 > than 25W?

Check the Astron supply carefully.  The RS-35 is a linear supply and
it is susceptible to failure of one/more of the pass transistors over
time, failure of one/more of the rectifier diodes, aging of the current 
sensing resistor with time or even simple loosening of the screws on
the capacitor.  Any of the age related issues could leave the RS-35
unable to provide more than 5A which would cause the K3 to shut down
at about 25 Watts output.

73,

    ... Joe, W4TV


On 3/23/2011 9:13 PM, David Lankshear wrote:
> Howdy, "H."
>
> Have you checked what your PSU is doing when you try to tx at more than 25W?
>
> Cycle round the options available by poking the "DISP" "METER" button and find the one that monitors your voltage input (it will be about 0.3v below your PSU voltage because of a protection diode).  Watch what happens to that voltage as you sneak up towards 25W.  If the voltage is showing a progressive drop, then you either have a sick PSU or there's a problem in the feed cable.  It's usually connections or an inline fuse where conductivity problems arise.
>
> Did you fit your own Andersons on the cable?  Did you solder and if you did, was the solder wicked inside the contact's barrel?  Did the contacts click home in the shells with a most definite click?  Once they've clicked into place they are very firmly there.  I think you have to experience trouble with an "un-clicked" Anderson before you really appreciate that click HI!
>
> Hope that helps, or at least keeps you busy for a while HI!
>
> Very best wishes and hope your problem is easily overcome.
>
> 73  Dave  G3TJP
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