power switch problem

[M0XDF]

My K3 appears to have developed a power switch problem - it won't turn  
off.
While away on Scout camp last week, I allowed another 2 hams to work  
the K3 while I was not present (one is quite young and the other an  
adult) - later on, one of them noticed that the K3 had turned itself  
on (after they had turned it off and walked away). The K3 was working  
correctly for the first few days and as far as I know, was not  
'bounced' around while sitting on the table during the week. All  
functions appear correct except for this.

After investigation, I found I can not turn it off. Pressing the power  
button results in one of the following behaviours:

Most common: LCD just shows background colour (light is on), LEDs are  
off, effectively the rig is off (no AF etc), but the LCD is not and I  
can't turn it back on with a press of the power button.

Occasionally: K3 turns off correctly, but then turns back within a  
matter of seconds.

Less occasionally: as above, but turns back on after a few minutes.

Rarely: Appears to turn off as per first scenario, but LCD flickers.

To resolve this, I have to pull out the power cord and plug it back  
in, in which case the K3 turns on - so it's like the power switch is  
permanently on.

This is not the ALARM function. In fact, I tried the alarm to see if  
it would turn on correctly - it won't, but it did bleep at me when I  
pulled the power out the back and plugged it back in.

I have tried a 'master reset' holding the power switch in, it make no  
different, doesn't reset and doesn't turn off etc.

In preparation for the reset, I went through and noted all the config  
settings, changing a couple on the way. After that, the K3 turned off  
ok, but came back on after a few minutes.

Holding the power switch while applying power results in the LEDs  
coming on, but nothing else.

I thought this might have been a problem with dampness, but the rig  
has been in my indoor shake for 3 days now. I also considered supply  
voltage, since at camp I was using a L/A battery, but its back on the  
13.615v supply now (I have a Medusa Research Power Analyzer).


I'm about to install the KRX3, so will be taking it apart, but would  
prefer to resolve this first.
Any suggestions?

This has been working perfectly since December.
73 de M0XDF, K3 #174

--
Study without desire spoils the memory, and it retains nothing that it  
takes in.  -- Leonardo da Vinci

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[M0XDF]

For those that replied and for anyone else for that matter :)
The problem with my K3 not turning off was a faulty KIO3 board (Pt#  
E850235), the one with the Acc. and RS232 connectors. Elecraft sent a  
replacement board and this resolved it.
I will post a description of the problem, steps taken to isolate it to  
the KIO3 board and possible solution (wash it!) to the Wiki asap.
--
Cats know exactly how we feel.  They don't give a damn…
but they know.

>
> -----Original Message-----
> My K3 appears to have developed a power switch problem - it won't turn
> off.
> After investigation, I found that pressing the power
> button results in one of the following behaviours:
>
> Most common: LCD just shows background colour (light is on), LEDs are
> off, effectively the rig is off (no AF etc), but the LCD is not and I
> can't turn it back on with a press of the power button.
>
> Occasionally: K3 turns off correctly, but then turns back within a
> matter of seconds.
>
> Less occasionally: as above, but turns back on after a few minutes.
>
> Rarely: Appears to turn off as per first scenario, but LCD flickers.
>
> To resolve this, I have to pull out the power cord and plug it back
> in, in which case the K3 turns on - so it's like the power switch is
> permanently on.

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