[Elecraft] K2 building problem
I've just finished the assembly of part 2 on the RF board and ran into a BFO problem during the testing on page 65 of the manual. All other tests have been right on the money to this point. When testing in the frequency counter mode the front display is changing rapidly when using the frequency counter probe inserted in TP2. If I tap the Band- button the display locks in at 4.91253. When I tap the Band+ button the display goes back to changing rapidly. I can measure a good solid reading at pin 6 of U11 telling me the BFO is working and the frequency displayed is 4.91253. I cannot get a reading for the BFO High Frequency. I've checked L33 and it's fine with no short caused by R116 being on top of it and has a good continuity across the windings. X3 and X4 are the correct crystals for that location and came from the package marked 4.91 MHZ. Anyone have an idea what the problem might be? Gary Auchard - WB0MNA K2 sn. 6506___ 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
Re: [Elecraft] K2 building problem
Gary, The frequency display changing rapidly is an indicator of one of 2 things. 1) The BFO oscillation is stopping, or 2) The BFO signal is too weak to be displayed properly by the counter. I would suggest that you check the soldering at X3, X4, C173.C174. RP6, D37 and D38, Q24, D36, R98, R99. Reflow the soldering with a hot iron (750 to 800 deg F) if necessary. 73, Don W3FPR Gary Auchard wrote: I've just finished the assembly of part 2 on the RF board and ran into a BFO problem during the testing on page 65 of the manual. All other tests have been right on the money to this point. When testing in the frequency counter mode the front display is changing rapidly when using the frequency counter probe inserted in TP2. If I tap the Band- button the display locks in at 4.91253. When I tap the Band+ button the display goes back to changing rapidly. I can measure a good solid reading at pin 6 of U11 telling me the BFO is working and the frequency displayed is 4.91253. I cannot get a reading for the BFO High Frequency. I've checked L33 and it's fine with no short caused by R116 being on top of it and has a good continuity across the windings. X3 and X4 are the correct crystals for that location and came from the package marked 4.91 MHZ. Anyone have an idea what the problem might be? Gary Auchard - WB0MNA K2 sn. 6506 ___ 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
[Elecraft] K2 building problem
Trying to put together K2 #5278 I am at the point for alignment and test Part 1. Powers up fine and shows 7100.00 c and display shows correct voltage and amperage. But when I test the optical encoder by turning the vfo knob it moves from 7100.00 c to 7100.01 c and then upon further turning moves back to 7100.00 c. Does the same thing no matter which way the knob is turned. Rechecked components and solder joint without finding anything. I may just be too old for this solid state stuff. I think the last thing I built was a HW 101. I did not try to go on to the calibration part as it may not be worthwhile with the encoder not working correctly. Appreciate any suggestions. K2 #5278 Ed Findley WB2KUI ___ 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
RE: [Elecraft] K2 building problem
Ed, You are going to find an unsoldered connection somewhere. Examine the boards carefully. One of the most likely is that you missed soldering a pin on one of the connectors, but examine everything. It is not your age - stuff like that happens to all of us at one time or another. 73, Don W3FPR -Original Message- Trying to put together K2 #5278 I am at the point for alignment and test Part 1. Powers up fine and shows 7100.00 c and display shows correct voltage and amperage. But when I test the optical encoder by turning the vfo knob it moves from 7100.00 c to 7100.01 c and then upon further turning moves back to 7100.00 c. Does the same thing no matter which way the knob is turned. Rechecked components and solder joint without finding anything. I may just be too old for this solid state stuff. I think the last thing I built was a HW 101. I did not try to go on to the calibration part as it may not be worthwhile with the encoder not working correctly. Appreciate any suggestions. K2 #5278 Ed Findley WB2KUI ___ 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
