[Elecraft] K2 Alignm.&Test, Part I, unexpected display of 160m band -- PROBLEM SOLVED

[Thomas Martin]

Hello,

finally I found an error I made which was responsible for the false 160m 
band display during Test and Alignment, Part I of K2 S/N 3105.

I installed R65 (10 kOhm) at the location of R63.
R65 (...well if present) pulls the 160RY signal at J14 (Pin 16) to 6V.
Looking to the schematic of the K160RX option this signal is fed back from 
K160RX to the RF
Board as 160RY (Pin 16). Taking into account only signal 160RY [and 
assuming RXRY or RY COM to be 0V] the voltage at 160RY will be 
about 0V if (...as in my case) R65 is not present or if R65 is present and 
the K160RX
option is installed (there is a voltage divider 
consisting of R65 and the two coils [in series] of relays K1, 2 on the
option board and the signal at the junction of R65 and the two coils is 
160RY).  
So it's not "astonishing" that the I/O controller decided that
the option was present.

Installing R65 at the correct location solved the problem.

Thanks to all members of the elecraft e-mail list who responded to my 
question.

Now back to Assembly of RF Board, Part II.

73
Thomas, DF7TV


-- 
Thomas Martin, Stuttgart, Germany
http://www.qsl.net/df7tv