[Elecraft] K3 shuts down

[G4GNX]

My K3S did this a couple of months ago - 40m SSB - 100W. I restarted it and it continued for nearly another month before switching off again. It did it a couple of times more over a week or so, before finally turning off and refusing to turn on again.

On investigation, I realised that I had “temporarily” connected the K3S power cable to a distribution box, using PowerPoles - bad move. When tracing the cable routing, I pressed against one of the PowerPoles and the radio came back on again. I found it impossible to pull the PowerPoles apart, which was due to the plastic covers being badly distorted by heat. I eventually got round to pulling the PowerPoles apart by force and unfortunately the + connector flew in the air and I haven’t found it yet. 😀

However, the contact in the dis-box looks suspiciously like it’s gotten hot and coupled with the other “evidence” I conclude that the contacts deformed under heat caused by high current spikes (SSB).

Also, my IC-9700 (although connected to a different PSU - via PowerPoles) did the same thing, but unlike the K3S, it just rebooted itself.

I have completely rewired all of the high power cables in my shack directly back to the PSU (Sharman Multicom - 60A) and I’ve had no more problems.

In your case, you’re running 100W for longer periods and that is one possible cause of a premature breakdown. You could save yourself a lot of trouble, by examining all of the power connections, including the PowerPoles on the K3 itself.

73,
Alan - G4GNX
South Coast UK
Elecraft K4D / KPA500 / KAT500 / IC-9700




> On 28 Aug 2024, at 03:30, Glenn Thorne <kd0q.glenn at gmail.com> wrote:
> 
> Just tonight my K3 with KPA3 running 100 watts shuts down during digital
> transmissions.  It appears that it happens after the PA temp is 47 C.
> Maybe the first time it hits 48 C?
> 
> I checked the KPA3 FN1 - 4 settings and it appears that the fans work.
> 
> At what PA temps should the fans come on?  Increased speed?
> 
> Any ideas where to start troubleshooting will be appreciated.
> 
> Glenn - KD0Q