[Elecraft] K2 #4498 - Big problem

[W3FPR - Don Wilhelm]

Bob,

First check your power supply and the cable connections between the Power
Supply and your K2.  The conditions you report are classic for a low voltage
at the K2 power connector and/or a high resistance (loose connection) in the
power supply path.

73,
Don W3FPR

> -----Original Message-----
>
>  Up to this morning, this K2 was a nice and good worker, with
> during the last
>  six month about a thousand QSO under his belt !
>  But this morning turning it on, I just got a vigorous howl (
> very low freq nois !). I turn it off, and
>  on after a few second.
>  The Rx start normaly and the noise start again after
>  a few second. Re-turn off and tunr on and no howl and Rx is working
>  correctly!
>  The set was in CW mode so I turn down power (to abt 2/3 watts)
>  and close the key...
>  The result is correct on 1.8, 3.5, 7.0 but nil on the rest of the bands.
>  Closing the key a little longer  on 7.0 the rig goes to
>  curent overange in abt 10/12 second and power fall down to zero.
>  So power off, open the rig, remove the bottom cover and before
> removing the
>  heat sink just check the resistance of driver and PA.
> On Q6 (driver) E to Gnd 1.3 ohm, B to Gnd 76/80 ohms, and C to
> Gnd > 500 ohms.
>  On Pa C to Gnd > 600 ohms, B to Gnd 120/130 ohm E to Gnd 0 (it's
> normal!).
> They seems to be normals but any time I close the key I get High
> Cur after 5/6 seconds and power out ZERO !!
>  I do not know what to do, so I will wait till tomorow and hope
> to get some
>  indications from the list !
> Thanks in advance guy, BCNU
> 72 Bob/F5UL
>
>