[Elecraft] FUSE BLOWN AND NOW WHAT?

[Don Wilhelm]

Manuel,

It is only a guess, but I would expect that the auto-resetting fuse in the
K2 is open, and possibly Doide D12 is shorted, or both.

With the K2 power switch in the ON position, check the resistance to ground
from the cathode of D10, you should measure more than 500 ohms - if it is
less than 500, turn the power switch to OFF and check again, this time the
resistance should be infinite.  If you have a low resistance with the power
switch in the OFF position, look for a short to ground (or a shorted D12).

If you do find a high resistance with the switch off, then connect your
power supply and measre voltages - first at the anode of D10, then the
cathode - next check at the center contacts of the power switch.  If you
have voltage at the cathode of D10 and none at the power switch, F1 is
likely open.

Good luck and let us know what you find.

73,
Don W3FPR

> -----Original Message-----
>
> Hello everyone:
> this time I have to come forward and confess with full exposure
> in broad day
> light. I made a terrible mistake!
>
> My KPA100 tested beautifully untill I got to the 20A power supply
> test (page
> 45). As I turned on the K2 (#8 step) nothing happened. I checked
> and I had
> blown a fuse (the one that comes with the kit). I switched off everything
> and went back to figure 32 (page 38)...I had reversed the wires
> on j4 when I
> soldered them on the KPA100 board.
>
> As I was taking my time to unsolder the cables, clean the pads etc. I
> thought I could  turn on the K2 on its own (as before) with my low power
> supply and nothing else attached to it. Well here comes the suprise...I
> cannot turn on the K2 at all. I have the 13,0 volts allright,
> coming out of
> my small PS but nothing happens. What did I blow away?
>
> J4 was plugged in P3, of course, when I blew the fuse.
>
> Your comments and recommendations will be very much appreciated.
>
> Thank you
> 73
> Manuel Wilches
> LU5OM
> CT4IK
>
>