[Elecraft] Dead K2 After nearby power surge

[Don Wilhelm]

Fred,

In cases like yours, first step is to connect a dummy load to the K2 
just in case it is trying to transmit - it is not good to enter transmit 
state without a load on the PA transistors.  If it is a K2/100, remove 
the KPA100 and connect the dummy load to the BNC antenna jack on the 
lower rear panel.

First thing is to check the state of the 8T and 8R voltage rails. Those 
are easily checked at the anodes of D6 and D7.  If D7 anode has 8 volts 
on it while D6 anode has zero volts, then the K2 is in a transmit 
state.  If both D7 and D6 anodes have 8 volts present, power it only 
briefly while making further checks lest some components overheat.

If both 8T and 8R are present, you need to check the state of the RX 
signal at the gate of control board Q4 as well as the TX signal at the 
gate of CB Q3 - one should be on (about 5 volts) while the other should 
be off (near zero volts).  If both of these are on, the microprocessor 
was zapped with the power surge, but if only one is on, the problem is a 
shorted Q3 or Q4 on the control board.

73,
Don W3FPR

Fred Keller wrote:
> I also just noticed that the power output transistors Q7 and Q8 are 
> getting warm when the power is on.  I did not say  before but, their 
> is no display or any other activity on the control board or front panel.
>
> Fred, KC9QQ
>
>