Harvey, At first glance it would seem like there is something awry with your wattmeter section of the KPA100. Check the T4 windings again and check carefully to be certain everything is well soldered with no solder bridges. Check the diodes for proper orientation, then try again to balance the wattmeter bridge. If you do not get the trimmer capacitor correct, the power and SWR indications will be 'funny', so be certain that you have a good null (use the DVM on the test point). The capacitor setting is quite 'touchy' so adjust it very slowly waiting for your DVM to settle down with each small change.
The increased voltages at D13 and U4 pin 8 are to be expected since the change of R4 to 39k - the voltages in the KPA100 unfortunately have not been updated to reflect this change. They are NOT related to your wattmeter problem. 73, Don W3FPR > -----Original Message----- > > Hello everyone. I almost made it to the finish line with my K2. > I'm encountering a problem with the KPA100 SWR Bridge Null > Adjustment (C1). I have everything hooked up correctly as far as > I can determine. I set the power knob for 5.0 W. Enter tune mode > and adjust C1 to get 1.0-1 SWR on the K2 display. The best I can > achieve is 3.6w and 3.4-1 SWR. When the display reads this value > my SX-200 power meter indicates about 18 watts out!! Also some of > the voltages read a little high: > > D13 cathode should be 90 to 150v : reads 158v. > U4 (MAX 1406) pin 8 should be -5 to -25v : reads -28v > > Test Equipment Used: DL-1 and MFJ dummy loads. > SX-200 power meter. > > I have given the board a close visual inspection and nothing > looks bad. The red and green leads on T4 go to the correct pads. > Any ideas? Thanks very much. > > Harvey KN6VP _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
