I'm in the process of building a K2 and am having trouble at the Alignment and Test part 2. I've gone through at ton of previous posts here an have been talking with Gary at Elecraft but no luck so far. The main issues are C22 only has adjustment less than 1khz (12085-12086) @ TP3, and R30 which should have 6V only has 0.02V.
Below is the email chain (bottom to top) with the trouble shooting Gary and I went through. Wonder if anyone has any ideas of what the issue might be, or further trouble shooting steps to isolate the problem. Thanks, Jeremy >From Jeremy To Gary Adjusting the windings on T5 and moving the slug in T30 up has given me 11914khz on 40m. The other bands are still way off. Cal PLL still gives error 232. I've tried running it at 7000, 7050, and 7100khz. Checked the diodes and all are correct and in the right spot. Oddly enough I was able to get it to run Cal PLL by turning T30 until I got 12003khz at TP1. Came across this by forgetting the probe in TP3 and running Cal PLL. Moved the probe to TP1 and adjusted T30 and Cal PLL ran. C22 only has an adjustment of less than 1khz (12085-12086) @ TP3. R30 which should have 6V only has 0.02V. Sent from my iPad On 2013-02-01, at 5:11 PM, Gary Surrency <[email protected]> wrote: The freq. is still too low at TP1. The PLL cannot lock and the VCO will not be on freq. unless it can tune to approximately the freq.'s shown in the VFO Table. Err 232 is what you will see when the TP1 freq. is not close enough for the PLL/VCO to lock onto the expected freq. Something still seems to be wrong too, with the VCO freq.'s on the upper bands. Too low of freq. means there is either too much inductance or too much capacitance in the T5 circuit. If it is not T5 and some bands are OK or close to OK, then it is likely that for some reason, there is too much C in the circuit still. This could be from an incorrect cap, a VCO relay is not releasing some of the caps, or the varactor diodes are of the wrong type or are in the wrong places. Check to see if maybe you mixed up the MV209 diodes with the 1SV149 diodes. Try expanding the red turns on T5 as much as possible, and turn the slug in L30 so it is near the top of the coil. See if then the VCO freq. will come close enough to the stated freq.'s for the PLL to lock when you do CAL PLL which is done only on 40m. If it is not within about 5-10kHz, CAL PLL will not succeed. -- 73, Gary AB7MY ========= [email protected] Elecraft Technical Support On 2/1/2013 4:52 PM, Jeremy Jones wrote: Understand totally on the capability of the radios. We're going to be using them as an easy way to practice and test improvised antennas. And if all goes well ill be passing my civilian amateur exam next week. Did the hard reset. U6 pin1 checks out good. U6 pin 5 is 4v. RFC 15 shows 2.3ohms. No marks on any relays. Removed 1 turn from T5. VCO test now gives 8040khz, which is now in spec. Still only 20mV on R30. All capacitors correct according to the VCO table. Still get error 232 when trying Cal PLL. New VCO freqs 3500khz = 8067 7000khz = 11734 10100khz = 13820 14000khz = 16559 18068khz = 18407 21000khz = 14847 24890khz = 16558 28000khz = 18405 Those are up from what you said was already high. What next :) Sent from my iPad On 2013-02-01, at 3:38 PM, Gary Surrency <[email protected]> wrote: Hi Jeremy, OK on the civilian call sign. Note that our radios are primarily intended to cover the US ham bands, and there is limited freq. coverage outside of those ranges due to the design of the VCO/PLL. The K2 is not general coverage. You might first try doing a hard reset by holding down the 4,5,6 buttons all at the same time when the power is turned on. This ensures the IOC sets the freq. boundaries correctly and all of the defaults are set. Release the buttons in 2-3 seconds and then wait about 10 seconds for the INFO 201 initialization to complete normally. This is usually done the first time the rig is turned on, but if it was interrupter or did not complete for some reason, the rig could be in an indeterminate state. The VCO frequencies you stated are too high. Try expanding the red turns on VCO inductor T5, or if necessary - remove a turn. Use care to not damage the plated through holes if you do need to remove T5 to rewind it. Be sure there is no mistake in ID-ing the caps in the VCO circuit too, and make sure none of the VCO relays have any soldering iron burns to their case, they are not reversed on the PCB, and the pins are well soldered. See the VCO Table again for which caps are used on which bands, and verify those are all correct, and they are well soldered, as well as the VCO relays that switch them. Check each and every part and soldered connection in the VCO / PLL area. Check that U6 pin 1 (LMC662) on the RF Board moves between 0VDC and about 7.5VDC when you do the PLL range test. If not, there is probably a problem with the little PLL reference oscillator thermistor board, usually a poor connection. Remove the left side panel, front panel and control boards to inspect it better. Reheat or resolder any suspect connections. Also check that U6 pin 5 (LMC662) in the PLL circuit, is steady at 4.0VDC. If not, the PLL thermistor board has a problem with the RE, RF 10k 1/8w resistors that set this level. In some cases, RFC15 may be broken, open, or not well soldered. Check it with an ohmmeter to be sure it shows less than 10 ohms across its leads. If it is open, the rig will work fine without it and a jumper in place of RFC15. <cdiidecb.png> -- 73, Gary AB7MY ========= [email protected] Elecraft Technical Support On 2/1/2013 3:15 PM, Jeremy Jones wrote: Hi Gary, I don't have a civilian callsign yet. These radios were purchased for the Canadian Department of National Defense. The name it was ordered under is likely Roger Rodrigue. D19 and D20 are not installed. D19 is set to n in the secondary menu. The frequency reading I am getting at TP1 is as follows 7000khz = 11219 3500khz = 7703 10100khz = 13230 14000khz = 15892 18068khz = 17703 21000khz = 14229 24890khz = 15891 28000khz = 17702 T5 checks out, as I had already rewound it. I have good connectivity to the board with it. All soldering has been checked and reheated to ensure no cold joints. What else should I check or try? Thanks, Jeremy Sent from my iPad On 2013-02-01, at 11:02 AM, Gary Surrency <[email protected]> wrote: Hi Jeremy, (Please always provide your call sign. We have 82 customers with the last name of Jones, and I could not find any of them with a first name of Jeremy.) Sounds like a fault in the VCO circuit and the PLL is not locked on freq. You need to check to see if there is a proper signal freq. at TP1 when the rig is tuned to the bottom of the 40m band and all other bands, as shown in the VCO Table below. If not, then check T5 and all of the other parts in the VCO circuit. Make sure D19 and D20 are *not* installed, and the "d19" entry in the Secondary Menu is be set to "n", not to "Y". These parts and the d19 setting are for the K60XV option. <ifhdegcb.png> -- 73, Gary AB7MY ========= [email protected] Elecraft Technical Support On 1/31/2013 8:13 PM, Jeremy Jones wrote: Good day, I am having a little trouble in the part 2 alignment and test of the K2 I am building (I can't seem to find the serial number sticker at the moment, but it was just purchased). When trying to adjust C22 to calibrate the PPL Reference Oscillator, I get no change from adjusting C22. I read that this might require a CAL FIL and CAL PLL. I did CAL FIL but CAL PLL give me an Error 232, even when tuned at various points on 40M. The 4MHz range test is fine, with a high freq of 12099.33 and a low of 12086.53. My reading on the VCO test is low at 7694.39. I am only get 20mV at R30, and no adjustment from L30. Doing the signal trace at the end of the manual resulted in 628mV for the Reference Oscillator output at pin 1 of U4. This reading should be between 0.8-1.8Vrms. All other readings for the Reference Oscillator, VCO and BFO were within specs given. I have tried numerous tests and checks that I've found on the internet, however nothing seems to address the low voltage at R30, which I think may be the cause of the other issues. The voltages on U6 are correct, except for pin 7 which is 20mV, which makes me suspect that might be the problem. Can you offer any other trouble shooting steps or measurements that may help me isolate the issue. Its been a great build up until now. Thanks, Jeremy -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-VCO-Alignment-only-0-02V-R30-tp7569523.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
