[Elecraft] K2 low voltage power down

[Don Wilhelm]

David,

Low DC voltage on D10 and D12 is not likely a K2 problem (unless there 
is a problem with the DC input jack).  Rather it is a problem with your 
power supply or the power cable.

Check the voltage at the center pin of the coaxial DC power jack.  If it 
is showing the same thing as D10, then you either have a bad power cable 
or a bad coaxial power jack.
OTOH, if the voltage at the center pin of the DC coaxial jack is OK, and 
the voltage at D10 drops significantly, look on the bottom of the RF 
board to see if the power PC trace between the coaxial jack and D10 has 
been damaged - if so, solder a wire in its place and scrape out the 
lifted parts of the PC trace so they do not cause inadvertent shorts.

If the voltage at the coaxial power jack also drops significantly, then 
your power supply or the power cable is at fault.

73,
Don W3FPR

On 10/27/2016 7:13 PM, David N. via Elecraft wrote:
> Hello all my k2  has problem
> Turn it on the s meter goes full up
> 5 seconds later says low voltage shuts off.
> I checked the display and the voltage is dropping and shut off at about 4.2 volts.
> I checked at the power jack d10 and d12 and show the same thing but voltage at these points drop down to 9.4v on DVM then shuts off. Checking diodes in circuit. I cannot get a real reading check short 1 direction and chargers up in the other. The resettable fuse appears to be OK.
> I tried resoldering the power, switch jacks and both diodes, to no avail.
> Any suggest?