Don, I found that I'd installed U7 backwards. U7 is at the heart of the bias control. I can't find a cross reference for LMC6482 at a couple of local parts stores. I don't know if removing it and reinstalling it will work. I am having problems removing and it may have been damaged.
I am trying to find a cross reference on the interent and seeing if a couple of parts stores might have it. They don't have a reference for it. 73, Steve N6VL -----Original Message----- From: Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Saturday, August 11, 2007 3:06 PM To: Steve Kallal Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA100 bias issues... Steve, Rotate the KPA100 bias pot back to its full counterclockwise position, make certain you have a good dummy load on the KPA100, and then try the steps below: First, determine if the current draw at 0.1 watts is high in the base K2 or the KPA100. Disconnect the ribbon cable to the KPA100 and measure the current draw - expect 240ma to 360 ma - this will depend on how many options you have installed - low end if you have no options and high end if your K2 has a full house (especially the KDSP2). If you have considerably more current draw than that, re-look at the base K2 for the cause. If your current draw is within range, power off and install the ribbon cable - the KPA100 will add some to the current draw found in the above step - expect 50 to 100 ma more.. Now turn the power up to 11 watts or higher - the current should increase another 100 to 150 ma depending on the state of the fan. When all the above is within range, put the K2 into CW TEST - that is very important. Add 400 ma to whatever the current draw was in the above 11+ watt check - that is your desired final bias current setting. Now press TUNE - at first the current will not increase very much, but with rotation of the bias pot, the current should increase. Find the place where the current increases about 400 ma and stop for now - you are close. Go out of TUNE by tapping any button - do not power off or you will lose the CW TEST condition (that is why you received the HI REFL message). Enter TUNE and quickly check the current draw and exit TUNE. The current draw will climb after a half second or so, but the initial reading on your DMM may be too low because the gate timing on your DMM is not synchronized, so look at the reading for the second scan - in other words wait more than a tenth of a second and less than half a second to see the correct reading. If the reading is too low adjust the pot slightly clockwise, but if it is too high, adjust it a tiny bit in the counterclockwise direction. 73, Don W3FPR _______________________________________________ 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
