Re: [Elecraft] [K2] K2-100 Test and Alignment Issues
Don, I am finally able to get back to my KPA-100 construction project and this email is to complete this thread with the result. Yes the problem was T4. I removed, rewound and replaced it. You were correct, I had wound T4 backwards. With the correction I was able to easily null the bridge to 12 millivolts. R26 and R27 required almost no adjustment to set the correct values. The rest of the setup and test process went perfectly. So, to those who are or will be building the KPA-100, keep in mind that T4 must be wound exactly as illustrated and instructed in the manual. Thanks again for your help, Don. Bill, VE2WMA -Original Message- From: Don Wilhelm [mailto:w3...@embarqmail.com] Sent: Thursday, January 30, 2014 4:50 PM To: William Moore; d...@w3fpr.com; elecraft@mailman.qth.net; 'Mike Harris' Subject: Re: [Elecraft] [K2] K2-100 Test and Alignment Issues Bill, Regarding T4, there is one other possibility that I did not mention before. If the direction of the windings is not as shown in the manual, it will work backwards which may be what you are observing. As for the minimum voltage of 1.4 volts, that is WAY too high. The bridge should null to less than 14 millivolts with 15 or 20 watts flowing through it. You could do a sanity check on it by attempting to null the bridge by monitoring the DC voltage at U5 pin 3 rather than U5 pin 1. The voltage on U5 pin 1 should be the same as at pin 3 if U5 is working OK. If you still have a high voltage at U5 pin 3, then try doing the balance (nulling) while monitoring U5 pin 5. If you can obtain a null at U5 pin 5, then for certain T4 is wound in the wrong direction. 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
Re: [Elecraft] [K2] K2-100 Test and Alignment Issues
Don, Thanks you for this tip, and yes, I now realize my windings on T4 are not exactly as shown in the manual. However this realization raises a broader concern. Here is what happened. I wound my toriods using a winding tip I'm sure I picked up on the Elecraft list some time ago. To wind the toriods, I put the wire(s) to be wound on the core through the toroid core half way, pull up the two ends at a 12 o'clock point on the toroid core then wind one lead counter clockwise to about 7 o'clock and the other lead clockwise to about 5 o'clock. I now realize that this will result in the toroid being would in reverse to probably the standard winding practice of starting only one long lead at 7 o'clock on the toroid core and then winding all the required turns on the core around to about 5 o'clock. I have now pulled, T4 and rewound it exactly as shown in the manual. I am ready to reinstall it but before I do, here is the broader concern. I have also reverse wound T3 as well as each and every other toroid core on the KPA-100! Do you think this will create problems such that I will have to remove, rewind and reinstall all the toriods, just certain toriods or is it just T4 that is an issue? What makes me wonder is that I built my entire K2 and the KBS2 using the 12 o'clock high two-lead core winding system and the K2 works just fine for me but then I can't verify if the my K2 is really performing exactly to specifications because I don't have test facilities to do so. I would really appreciate your comments on this issue before reassembling the circuit board back onto the heatsink in case I need to make other changes to the toriods. Thank you. Bill, VE2WMA -Original Message- From: Don Wilhelm [mailto:w3...@embarqmail.com] Sent: Thursday, January 30, 2014 4:50 PM To: William Moore; d...@w3fpr.com; elecraft@mailman.qth.net; 'Mike Harris' Subject: Re: [Elecraft] [K2] K2-100 Test and Alignment Issues Bill, Regarding T4, there is one other possibility that I did not mention before. If the direction of the windings is not as shown in the manual, it will work backwards which may be what you are observing. As for the minimum voltage of 1.4 volts, that is WAY too high. The bridge should null to less than 14 millivolts with 15 or 20 watts flowing through it. You could do a sanity check on it by attempting to null the bridge by monitoring the DC voltage at U5 pin 3 rather than U5 pin 1. The voltage on U5 pin 1 should be the same as at pin 3 if U5 is working OK. If you still have a high voltage at U5 pin 3, then try doing the balance (nulling) while monitoring U5 pin 5. If you can obtain a null at U5 pin 5, then for certain T4 is wound in the wrong direction. 73, Don W3FPR On 1/30/2014 4:39 PM, William Moore wrote: Don and John, Thank you so much for coming to my aid with these baffling (to me) problems. I have undertaken both your suggestions but still, unfortunately, no joy. The J3+ issue The J3+ lead now gives a voltage reading of -0.225 volts while covering the PA transistors with a thick cardboard and a mostly darkened room. I can also confirm, absolutely, that no 13.8 volt current has ever passed through J3 or the Aux 12 volt line to the K2. The Wattmeter issue. I reset R26 and 27 to 43K and tried once again to balance the wattmeter with C1. Twisting C1 with a plastic handled screw driver, I got the voltage at Test Point 4 down to 1.4 volts but I am not sure if that is what you mean by close to 0.0 volts. At the same time, glancing at the K2 LCD it still shows a 9.9::1 swr and the watt meter on my Kenwood AT-200 antenna tuner bypassed to a dummy load indicates the K2 is pumping out a full 15 watts. Varying C1 while looking only at the K2 LCD, I can get 1.0::1 SWR but the power out on the LCD registers 0.1 watts while the AT-200 wattmeter says the K2 is still pushing 15 watts to the dummy load. Varying C1 does not change the 15 watt output on the KAT200 watt metre. It always remains at a constant 15 watts. I then disassembled the KPA-100 circuit board from the heatsink. I checked that all the components you listed were the correct values and oriented properly i.e., D16 and D17. I checked the solder joints until my eyes crossed with a lamp having a magnifying lens in the centre of the fluorescent bulb. I found no solder bridges, unsoldered leads or poorly soldered solder pads. I thinks John's problem that he referred to in his post was a solder bridge between R24 and R26 but I found this junction was clean of any hint of a solder bridge. I found no protruding grounding leads anywhere. I am quite sure but, not absolutely sure, that T4 is wound (12 turns twisted wire counted inside the core), wired and soldered correctly with no leads shorting. The T4 solder pads are full with bright silvery solder, no craters and the solder flows through the holes to the top of the circuit board. The only variable that I can see left is to pull T4, rewind and reinstall
Re: [Elecraft] [K2] K2-100 Test and Alignment Issues
Don and John, Thank you so much for coming to my aid with these baffling (to me) problems. I have undertaken both your suggestions but still, unfortunately, no joy. The J3+ issue The J3+ lead now gives a voltage reading of -0.225 volts while covering the PA transistors with a thick cardboard and a mostly darkened room. I can also confirm, absolutely, that no 13.8 volt current has ever passed through J3 or the Aux 12 volt line to the K2. The Wattmeter issue. I reset R26 and 27 to 43K and tried once again to balance the wattmeter with C1. Twisting C1 with a plastic handled screw driver, I got the voltage at Test Point 4 down to 1.4 volts but I am not sure if that is what you mean by close to 0.0 volts. At the same time, glancing at the K2 LCD it still shows a 9.9::1 swr and the watt meter on my Kenwood AT-200 antenna tuner bypassed to a dummy load indicates the K2 is pumping out a full 15 watts. Varying C1 while looking only at the K2 LCD, I can get 1.0::1 SWR but the power out on the LCD registers 0.1 watts while the AT-200 wattmeter says the K2 is still pushing 15 watts to the dummy load. Varying C1 does not change the 15 watt output on the KAT200 watt metre. It always remains at a constant 15 watts. I then disassembled the KPA-100 circuit board from the heatsink. I checked that all the components you listed were the correct values and oriented properly i.e., D16 and D17. I checked the solder joints until my eyes crossed with a lamp having a magnifying lens in the centre of the fluorescent bulb. I found no solder bridges, unsoldered leads or poorly soldered solder pads. I thinks John's problem that he referred to in his post was a solder bridge between R24 and R26 but I found this junction was clean of any hint of a solder bridge. I found no protruding grounding leads anywhere. I am quite sure but, not absolutely sure, that T4 is wound (12 turns twisted wire counted inside the core), wired and soldered correctly with no leads shorting. The T4 solder pads are full with bright silvery solder, no craters and the solder flows through the holes to the top of the circuit board. The only variable that I can see left is to pull T4, rewind and reinstall. However, before I do this, is there any other measurements, checks or procedures that I have overlooked or new ones that can be suggested? My career background is in the field of business and economics so I kind of feel like I am an auto mechanic trying to diagnose and perform surgery on a complex cardiology problem. That is to say, I really appreciate your help. 73 Bill, VE2WMA -Original Message- From: Don Wilhelm [mailto:w3...@embarqmail.com] Sent: Monday, January 27, 2014 2:58 PM To: William Moore; elecraft@mailman.qth.net Subject: Re: [Elecraft] [K2} K2-100 Test and Alignment Issues Bill, For the J3+ lead, I think the PA transistors may be producing that voltage in response to light shining on them. Shield the transistors from light and see if the voltage changes - if so, ignore it. As for the C1 adjustment - do the following steps in order. Preset R26 and R27 to about mid-range. If you want a closer setting, measure the resistance to ground from the center pin on the pot and set it close to 43k - you can measure from U5 pin 3 and pin 5 for easier access than the actual potentiometer. Balance the wattmeter by adjusting C1 - monitor the voltage at TP4 while sending 40 meter power through the wattmeter. You should be able to obtain a very near zero voltage if all is well. If you cannot obtain a very low voltage, there is a problem with one or more of the following: T4, D16, D17, R28, R29, C95 or C1. Check the windings of T4 first to be certain the correct leads are in the right holes and have been well stripped and tinned (if there is any question, rewind T4 with new wire). Then check the orientation of D16 and D17 against the parts placement diagram at the back of the manual. Be certain all the parts I mentioned are well soldered and there are no solder bridges. T4 does have a 3rd winding, and that is the red wire from the center of the SO-239 jack to the board for T4-6 and the bare wire from the center of the SO-239 to the board hole marked T4-5. Be certain the bare wire is not touching the shell of the SO-239 and was trimmed so it is not grounding against the heatsink. Once you have achieved the balance point for C1, do not change its position. Adjust R26 during a TUNE to indicate the same power on the K2 display as you read on your external wattmeter. Then adjust R27 to the same position as R26 unless you have a load which can produce a known SWR below 2.0:1, in which case you can use that load and adjust R27 until the K2 shows that known SWR. You can initially set R26 and R27 with the low power from the base K2 (do not connect the APP power cable). Later you may want to refine the R26 setting using 80 or 100 watts. Let us know how you make out. 73, Don W3FPR On 1/27/2014 2:02 PM, William Moore wrote: I am now
[Elecraft] [K2} K2-100 Test and Alignment Issues
I am now into the test and alignment phases of my just constructed KPA-100 amplifier to be integrated into K2 #3842. Right from the start of this phase, I have run headlong into a two issues I just can't figure out. I am constructing from the Revision G September 2010 manual. On the page 47, the voltage test chart, all measurements are in accordance with the ranges in the chart except for J3+ lead where instead of 0 volts, I am reading a stable and consistent 0.044 volts; certainly not a significant voltage but none the less, it is not zero as called for in the chart. The second issue is with reference to the C1 SWR Bridge Null Adjustment described on page 48. Adjusting C1 varies the power output reading on the K2 LCD but does not vary the SWR readout which remains at 9.9 to 1. However, the SWR/watt meter on my Kenwood AT-200 antenna tuner indicates the K2 is running 15 watts with an SWR of 1 to 1 into the dummy load, a Heathkit Cantenna. Twisting the power pot has no effect on the actual power output as measured on the Kenwood AT-200. Removing the all connections between the K2 and the KPA-100, the K2 functions normally with the power setting pot. I would really appreciate hearing from anyone who can offer any clues to what I am doing wrong in conducting these measurements and adjustments or perhaps identifying a possible construction mistake but gee, I checked so carefully. Thank you, Bill, VE2WMA __ 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
[Elecraft] K2 KPA100 T1 and T2 solder installation
I am about to solder transformers T1 and T2 onto my KPA100 board and request some guidance as to type of soldering iron to use. Equipment available to me for soldering is a 35 watt soldering iron with a 1/8 inch wide chisel tip or a soldering station adjustable to over 900 degrees,F, with a about a 0.8 mm chisel tip. Do either of these soldering tools qualify as a heavy soldering iron as suggested in the instructions? Which of the two available to me would be best to use in this application and, if neither, what type and wattage of soldering iron would be recommended? Any advice for this critical installation would be appreciated. Thank you, Bill, VE2WMA __ 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
[Elecraft] Keyer Monitor Pop
Greetings, On my K2, serial 3842, using the internal keyer, I always get a key pop sound but only on the initial make (the first dit or dah upon the rig cycling from rx to tx). It is sounds popping sound like a low frequency click or thud. It particularly annoying when using my Kenwood HS-5 headphones. My signal, when monitored on the air, is clean so the pop is not transmitted. Therefore, the problem must lie in the keyer monitor. Can someone advise where I might begin my troubleshoot or offer a solution? Thank you. Bill Moore, VE2WMA ___ 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 3842 Calibration Blues
Hi all, This posting (appears below) may be recalled from last week. Boy is my face red! It turns out that Dan Barker, WG4S, was right. There was no problem with the K2, just the builder. Thanks to Dan's reminder, I have finally realized the K2 Calibration imperative If the reference oscillator, is reset and CAL PLL is run, it is imperative that CAL FIL also be run for all modes and all filters used Having followed this imperative, my dial calibration is now within 20 Hz, using Spectrogram to align the filters. I had thought that since the filters were previously set satisfactorily, I shouldn't have to do it again after running CAL PLL. Wrong!! They do! As my father told me Son, there are occasions where it matters not what you think, it matters only to do what you are told and this is such an occasion. This certainly applies to me in this instance. Thanks to Dan, WG4S and Stu, W6CUX for helping me finally understand the K2 calibration imperative. 73, Bill, VE2WMA From: William Moore [EMAIL PROTECTED] Subject: [Elecraft] K2 3842 Calibration Blues To: elecraft@mailman.qth.net Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii Hello all, I am trying to fine tune the dial calibration and filters with Spectrogram. I do believe that I have tied all the procedures available to accurately set C22 to precisely align the 4000.00 reference oscillator. However, regardless of method used and after running CAL PLL and CAL FIL, the dial readout is 250 Hz above what it should read on USB and 250 Hz below on CW normal but spot on in CW reverse. Yes, I ensure that TP-1 is connected for running CAL PLL and TP-2 for running CAL FIL. The CAL PLL linearization process seems to proceed normally. All PLL, VCO and BFO tests are perfectly within range; R 30 reads a healthy 6.07 volts, CAL FIL has been perfectly set (in CW only) with Spectrogram. The radio performs perfectly in all other respects. I should point out that K2 3842 is currently just a basic K2, no add on accessories as yet. For reference frequencies using the W3FPR method, I used CHU on 3330 MHz and 7335 MHz (both are USB transmissions with carrier reinserted), W1AW on 7047.75 CW normal and WWV 1.00. Given current band conditions, WWV is pretty weak way up here in north-eastern Quebec and I don't always get a very good reference for Spectrogram. For most all of my alignment attempts, I used a combination of the W3FPR method for us tone challenged persons and then the N6KR system to mathematically set C22 using the frequency readings at TP-1 and TP-2. So, I am stuck. I can only conclude that the DAC is either adding or subtracting 250 Hz to dial read out. But hey, what do I know? My background is economics and the rules of supply and demand don't apply to this case. Can anybody shed some light on what I am doing wrong in the alignment process so I can resolve my calibration blues. Thank you and 73 Bill, VE2WMA ___ 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 3842 Calibration Blues
Hello all, I am trying to fine tune the dial calibration and filters with Spectrogram. I do believe that I have tied all the procedures available to accurately set C22 to precisely align the 4000.00 reference oscillator. However, regardless of method used and after running CAL PLL and CAL FIL, the dial readout is 250 Hz above what it should read on USB and 250 Hz below on CW normal but spot on in CW reverse. Yes, I ensure that TP-1 is connected for running CAL PLL and TP-2 for running CAL FIL. The CAL PLL linearization process seems to proceed normally. All PLL, VCO and BFO tests are perfectly within range; R 30 reads a healthy 6.07 volts, CAL FIL has been perfectly set (in CW only) with Spectrogram. The radio performs perfectly in all other respects. I should point out that K2 3842 is currently just a basic K2, no add on accessories as yet. For reference frequencies using the W3FPR method, I used CHU on 3330 MHz and 7335 MHz (both are USB transmissions with carrier reinserted), W1AW on 7047.75 CW normal and WWV 1.00. Given current band conditions, WWV is pretty weak way up here in north-eastern Quebec and I don't always get a very good reference for Spectrogram. For most all of my alignment attempts, I used a combination of the W3FPR method for us tone challenged persons and then the N6KR system to mathematically set C22 using the frequency readings at TP-1 and TP-2. So, I am stuck. I can only conclude that the DAC is either adding or subtracting 250 Hz to dial read out. But hey, what do I know? My background is economics and the rules of supply and demand don't apply to this case. Can anybody shed some light on what I am doing wrong in the alignment process so I can resolve my calibration blues. Thank you and 73 Bill, VE2WMA ___ 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
