K2 RF Board Test II
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I've completed the tests and alignment in Part II of the RF board. All resistances and voltages are within given ranges. Everything seems to work except that when I tune through a signal (CW or BC) in CW mode on 40 meters, the pitch of the received signal doesn't change. The signal pops up when it hits the first filter skirt, doesn't vary in pitch as I tune accross it, and it disappears on hitting the other skirt. In SPOT mode, I hear the sidetone, but nothing varies. I did the VCO/BFO signal tracing bit, and all voltages are within tolerance.
Any ideas? 72, John W9LHG _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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John,
This is the normal behavior is the proper VCO values are not entered into the EEPROM. If you have not yet run the CAL PLL procedure, that is explaination enough. If you have run CAL PLL, put the bottom cover on and re-do it. If you then still have trouble, we can help with detailed troubleshooting of the PLL and VCO areas. 73, Don W3FPR > -----Original Message----- > > I've completed the tests and alignment in Part II of the RF > board. All resistances and voltages are within given ranges. > Everything seems to work except that when I tune through a signal > (CW or BC) in CW mode on 40 meters, the pitch of the received > signal doesn't change. The signal pops up when it hits the first > filter skirt, doesn't vary in pitch as I tune accross it, and it > disappears on hitting the other skirt. In SPOT mode, I hear the > sidetone, but nothing varies. I did the VCO/BFO signal tracing > bit, and all voltages are within tolerance. > > Any ideas? > > 72, > > John W9LHG > > > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.394 / Virus Database: 268.10.1/391 - Release Date: 7/18/2006 > > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by John Lyon-4
John,
The VCO frequency of 8903 kHz is not correct for the 40 meter band. I would be willing to wager that you have installed the 'Rework Eliminators' which includes the changes to the RF Board for the K60XV. The K2 manual clearly states that one should NOT install the K60XV components until the K2 has been properly tested, but it seems the instructions from the Rework Eliminator guys ignore that and just say to 'do it anyway'. Since you have already installed the 120 pf cap for C71 and installed D19 and D20, you will have to operate it as if the K60XV is installed, so set the D19 parameter in the menu to ON and then re-run CAL PLL and CAL FIL as instructed in the K2 manual. You are not able to properly check the VCO range (voltage at R30) at the critical points until you actually install the K60XV, so just check all band edges to be certain they are within range and make a mental note to re-check those VCO ranges after installing the K60XV option. Don't be overly concerned about the voltages at those pins of U6, U7 and U8 - these are digital signals and if the K2 display and front panel buttons are working properly, those signal paths are likely just fine - there is confusion over whether the high or low state should be listed in the DC Voltage Chart, because the conditions to produce each reading are not always present. 73, Don W3FPR -----Original Message----- Hi, Don, and tnx for the reply. Here are the values that I got: PLL 12098.74 12086.09 range 12.65 VCO 8903.42 BFO 4913.61 4917.06 4912.72 difference 4.34 I have done the PLL/VCO/BFO process three times now. They were consistent each time. Since you mentioned the EEPROM, the trouble shooting section pointed to U7 on the Control Board. All voltages were correct except pin6 which was 5 volts instead to zero. Going forward and backward, U8 pin 6 on the RF Board, and U8 pin10 on the Control Board, are both 5 volts instead of zero. I don't know where to go from there. I truly appreciate your help and have observed on the list that you are most knowledgeable. Elecraft said to do the CAL PLL and CAL FIL processes. I have done them both multiple times, with no change in result. _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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