Re: My K2 died.

Posted by w3att on
URL: http://elecraft.85.s1.nabble.com/My-K2-died-tp7601542p7601564.html

Don,

Yes they are all on the control board. I have checked all input voltages to IC's and all are good.

U1, pin 8 - 8v
U2, pin 8 - 8v
U3, pin 8 - 13.8v
U6, pin 1, 11, 32 -5v
U7, pin 8 - 5v
U8, pin13 - 5v
U9, pin 7 - 13.8v
U10, pin 4 - 8v

Don Wilhelm-4 wrote

Brian,

I assume those ICs are all on the Control Board.
If so, it does sound like the MCU is gone.  The best way to check that
is to substitute a new one.
However, some of the pins you measured are inputs to the MCU, so I can't
be certain if that is the problem or not.
It is unusual for the MCU to just go "Poof".  Some more methodical
measurements with the schematic in hand and a bit of logic would be
helpful.  Do you have the proper voltage at the power input pins of each
IC for starters.

73,
Don W3FPR

On 4/19/2015 10:07 PM, w3att wrote:
> K2 S/N 757 F/W 2.03d
>
> I was having some trouble with low power output through the K2 auto tuner..
> getting only about 1 watt or so into a dummy load.
>
> I had the cover off looking for any troubles. I disconnected the auto tuner
> and connected the dummy load to the ant out on the k2 and had full power out
> from there.
>
> While sliding the radio so that I could see inside a little better, the rig
> triggered tx and made a few dahs, go t real loud, then I heard what sounded
> like something short in the audio and smelled an odd odor.. this all
> happened within a second or two and it was too late.
>
> The entire radio shut down and I have no display, no relays click when I
> power on, no s meter etc.
>
> Checking inside, I do have power all through the power supply.. 8v and 5v to
> the MCU.. there, however, is where things go awry.
>
> No Tx or Rx. No power on pin 3, 6, 13, 19, and all other pins that should
> show 5v are either dead or showing only .1v or .2v
>
> I'm thinking the MCU? but I really can't figure out what caused it since
> nothing was touching bare wire when the catastrophe occured.
>
> Other symptoms include no voltage on U7 pins 1 and 2; U8 no voltage on pin
> 1, 9, or 11.
>
> I sure hope I can fix this.  This is my favorite rig.
>
> Brian W3ATT
>
>
>
>
>
> --
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