[Elecraft] [K2} K2-100 Test and Alignment Issues

John Oglesby oglesby91 at gmail.com
Tue Jan 28 15:31:42 EST 2014


Bill - I had this exact problem on my K2/100 during testing.  Changing 
C1 varied the power output, but the SWR was fixed at 9.9-1.  The problem 
was a short between the output of the two op-amps U5A and U5B that 
amplify and buffer the forward and reflected voltages before they go to 
the processor.  There are two resistors on the outputs that are very 
close to each other and the pads were shorted so the processor saw the 
same voltage for forward and reflected - ergo SWR of 9.9-1. And the 
voltage varied with the C1 setting as the bridge went in and out of 
balance - ergo the varying power indication. Totally a build error. 
When I folded over the resistor leads, they ended up looking like they 
were on a single pad.  I think if you  look at that area you will find 
the problem.

Good Luck.

73
John
N9RE


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