Afternoon all: K2 #6272 is alive and well once again.
Had a heck of a time getting the Q7 & Q8 installed. Kept seeing a short to the heat sink. Turned out the corner of the tab on Q7 had a raised area and a slight sharp spot that was cutting through the thermal pad and shorting to the heat sink when the screw was tightened in the tab. Fixed that and all back together. 14.5 watts out on 40 meters into a dummy load with 2.42 amps draw. Much better. 10 meters shows 12 watts out with 3.15 amps draw. RX and TX working fine on all bands and the KAT2 doing it's job just fine. K60XV is not on the board at this time. Jumpers are in place for now. I did test voltage on the base of Q7 & Q8. Both showing .63 volts while tuning. Now that the base K2 is up and running, it's time to tackle what ever ails my K60XV.............. No solder bridges at 8T so I'm diggen in to see what gives. Thanks to all for your suggestions / help: 72 Jerry N0JRN > The K60XV should not reduce the base voltage at Q7 and Q8. BUT, since it > is, remove the K60XV, put a jumper wire from pin 3 to pin 5 on J13 and > stick the leads of a small value capacitor (4.7 pF is ideal) into pins 1 > and 3 of J15. The K2 should operate normally except for 60 meters with > that jumper/cap combination in place. > > The 0.64 volts is within range, even though it is a bit on the high side > of what I normally like to see. > > As far as the K60XV problem, if your K2 has a serial number less than > 3000, while you have the heat-sink removed, check the cut that was made on > the 8T voltage line to pin 6 of J13 (see the K60XV installation > instructions). If the cut was not complete it would interfere with the K2 > power control as well as dragging the 8T voltage rail down. > If your K2 is later than SN 3000, look for a solder blob making a bridge > to the 8T voltage rail near J13 pin 6. > > 73, > Don W3FPR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
