[Elecraft] KAT500 refuses to turn on

[Ken Winterling]

Jim,

If you don't have a schematic you should download one.  According to the
schematic there isn't any internal fuse.
The 12VDC is passed from the rear panel jack through a polarity protection
diode to a choke then to a voltage regulator, a LM7805.

To start, you need to open the case and check that there is 12V on the jack
*inside* the case.  Then check if there is 5V at the regulator output.

If there isn't 5V at the outout check the regulator input side for
approximately 12VDC and work back through the choke and diode until you
find the defective component.

If the LM7805 has 5V on the output then it is likely there is a logic
failure and you should contact Elecraft.

Gl!

Ken
WA2LBI


On Thu, Feb 14, 2019, 09:01 Jim Douglas via Elecraft <
elecraft at mailman.qth.net wrote:

> Hi All,I have the K line here. I was listening to a QSO and out of the
> blue my KAT500 lost power.I disconnected everything from the KAT500 and
> then reconnected. The power plug has 12 volts so that is not the
> problem.The KAT500 was set up to turn on automatically when I turned on the
> power supply and now that does not work anymore.When I press the mode
> button to turn on the tuner that does not work now either. Where do I start
> looking?


Thanks, Jim Douglas  K2ZF
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