[Elecraft] K2/KSB2 problem

[Don Wilhelm]

Bob,

That sounds like the K2 is going into transmit.  Check the voltage at 
KSB2 P1 pin 3.  If that voltage is in the vicinity of 8 volts, it is 
going into transmit.  When in transmit, the receiver is muted and the 
LED bargraph indicates relative power output.
If that is true, turn power off and check the resistance from P1 pin 4 
(/PTT) - if the resistance is low or zero, then there is a short 
somewhere on that signal line, perhaps a solder bridge somewhere on the 
KSB2 board.

73,
Don W3FPR
.
On 5/11/2013 11:56 AM, F5UL Bob wrote:
> Hello all the team, particularly DON!
>
> Since some week I had a KSB2 problem. The K2 is working perfectly in CW, alone, or with the KPA100,
> with the KSB2 position jumpered. If I put KSB2 in place, the K2 Smeter display go to S9 + 40
> block the receiver and too, does not switch in Tx when I close either the key or the mike PTT.
> I did this morning voltages test on KSB2, and the following list is the values not normal, as
> indicated page23 of KSB2Assembly instruction :
>
> U1-12 = 5.02 (TXC)
> U1-14 = 5.21
> U1-16 = 0.00
> U1-17 = 5.23
> U1-21 = 0.00 (RXS)
> U1-22 = 4.27 (RXC)
> U1-28 = 4.92
>
> U2-5 = 5.36
>
> U3 OK
>
> U4-3 = 5.24
>
> All these values where obtained in Rx. I did not check them in Tx as it was impossible to switch in Tx mode!
> All values not noted where per the book!
>
> If I remember well, the U1 is a new one!
> Best regards to Elecraft
> F5UL Bob
>
>