KAT100 Power Calibration Problem

Posted by JeremyJones on Feb 28, 2014; 1:11am
URL: http://elecraft.85.s1.nabble.com/KAT100-Power-Calibration-Problem-tp7584832.html

I have just finished my KAT100, and am having an issue during the Power Calibration of R3 and R4.  I am using a K2 with KAT2.  I have a cable running from the Ant 1 jack of the KAT2 to the Ant 1 jack of the KAT100.  The KAT100 RF In jack is connected to the Transmitter jack of the power sensor of my W2.  The Load jack of the W2 sensor is connected to a 250W, 50 ohm dummy load.  The K2 is set for 10W.  The W2 is inline only to check the actual power out, due to the strange readings I was getting.  

When I hit TUNE, I can only get a voltage range of 0.0 to 0.07 VDC at U5 pin 5 while adjusting R4.  The table in the manual indicates that I need to set R4 so that I get 1.8V at U5 pin 5.

I have double checked the orientation of the diodes, everything checkout in the previous tests.  T4 has the correct windings, and continuity between pads 1 and 4 is good.  

What else should I be looking at.

Thanks for any help,
Jeremy
VA3ZTF