[Elecraft] K3 Suddenly died

[Lewis Phelps]

Thanks for input.  We can all stand down on this one.

The problem turned out to be a power cable after all.

I was using a 3' power cable assembled with fairly light wire (16 gauge).  Over time, the wire had flexed sufficiently at the exit from the APP pin that it began to fray. Fraying let to higher resistance, which led to more voltage drop under load, which led to further decay of the wire-pin joint. 

At the point I reported the problem, the power cord was still showing nominal voltage when not connected to the rig. But (apparently) resistance had risen to the point where the K3 wasn't getting sufficient voltage.  All this eventually became clear when the wire was completely cooked, broken, and charred on the end. 

I shudda tried a different power cord sooner. 

Lesson learned:  don't use 16 smaller gauge wire with Anderson Power Pole connectors, even if you double the wire to fill up the void in the pin.  It's still a single stranded wire where it exits from the pin, and the smaller wire size is more vulnerable to flexing, no matter how low the current demand of the load it's carrying. Eventually, this wire can (and did) become a 1 amp fuse.

73,

Lew N6LEW

PS I don't know the answer to Mike Roger's question about IMD, but I'm willing to bet that the answer is, "not a problem." I trust Elecraft's engineers to pay attention to that sort of thing.

lew



Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10 
Yaesu FT-7800 
Lew at N6LEW.US
www.ntlew.us



On Oct 6, 2013, at 10:38 AM, Wayne Burdick <n6kr at elecraft.com> wrote:

> The K3 can safely be set to its maximum QRP/QRO power levels. If any operating limit is exceeded (temperature, voltage, current drain, SWR, reflected power, etc.), power will automatically be rolled back.
> 
> While this protects the radio 99.9% of the time, things can happen -- lightning, ESD, component failure, Acts of God, pet disasters, 8-year-old-boys, etc.
> 
> In the present case, some quick resistance or voltage checks might reveal what's going on. Check the Troubleshooting section of the manual, which is pretty extensive and can help you solve most problems. If that doesn't do it, call customer support.
> 
> 73,
> Wayne
> N6KR
> 
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