KPA100 Power Malfunction
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When the KPA100 is not installed, my K2/QRP operates normally.
However, with KPA100 installed I have no incremental power control and no lit LEDs on the K2 S/RF meter. The SWR is indicated to be 1:1 into an OHR RFL 100 Dummy Load. "HiCur" does flash on momentarily after switching to the 80 & 40 meter bands. I am using my straight key to key the K2... not TUNE. First test on 40Mtr band: Both Hi Current and Lo Current Power Supplies on: Requested power = .1 to 10w, power to dummy load = 20w Requested power = 11 to 110w, power to load = 110w With only Lo Current Power Supply on: Requested power = .1 to 15w, power to load = 10w I cycled DC power off/on: Requested power = .1, power to load = .3w Requested power = 10, power to load = 10 I backed off requested power: Requested power = .1, power to load = 10w I turned Hi Current Power Supply on: And raised requested power: Requested power = 20w, power to load = 110w Then backed off again: Requested power = 9.5w, power to load = 10w Band Initial Power readings after I raised (Mtr) Power requested pwr past about 1w. (With Hi and Lo Current Power Supplies on:) 160-15 0 20, 110 12, 10 0 3, 25 (With only the Lo Current Power Supply on:) 160-15 0 10, 10 12, 10 0 3, 3 (The lower power readings read when =< 10W requested, the higher power readings read when > 10W requested and the Initial Power is what I read just after switching bands) "HiCur" does flash on momentarily after switching bands. There are no INFO ### messages. My equipment for this test: OHR WM-2 (QRP) and Heathkit HM-2140 (QRO) watt meters and OHR RFL 100 and Heathkit Cantenna dummy loads. The testing steps during the KPA100 build checked out properly. I have double checked the solder joints and reworked those that I thought might have been questionable with no change in the (mis)behavior. I don't know if these findings are of any help to you... I would be glad to supply whatever readings as I may be able. Troubleshooting suggestions appreciated! Thanks, Ed - AD7GR K2 #6050 _______________________________________________ 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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Ed,
Lack of power control with the KPA100 installed normally points to a failure of the KPA100 wattmeter circuit. Start with replacing the 1N5711 diodes D16 and D17. It could also be that U5 and/or U6 are not performing properly. If your KPA100 was working at one time and there is *any* possibility that you encountered a lightning surge, then D16 and D17 are the most likely suspects. If it has not worked before, look at the soldering (especially U5 and U6, check all 6 leads of T4 for proper orientation and tinning - make certain the red wire goes through the center of T4 and the bare wire from the SO239 jack goes to hole #6. There are a few other possibilities, but those should get you started on the right track. The bottom line is that the base K2 is not getting a proper indication of power output from the KPA100 wattmeter and the base K2 develops full output because it thinks the power output is low - in other words, you do not have power control. When you totally remove the amplifier and the power control is restored to normal, that indicates that the K2 power control is functioning and the problem is in the KPA100 wattmeter. 73, Don W3FPR eKotz wrote: > When the KPA100 is not installed, my K2/QRP operates normally. > However, with KPA100 installed I have no incremental power control and > no lit LEDs on the K2 S/RF meter. > > The SWR is indicated to be 1:1 into an OHR RFL 100 Dummy Load. "HiCur" > does flash on momentarily after switching to the 80 & 40 meter bands. > I am using my straight key to key the K2... not TUNE. > > First test on 40Mtr band: > Both Hi Current and Lo Current Power Supplies on: > Requested power = .1 to 10w, power to dummy load = 20w > Requested power = 11 to 110w, power to load = 110w > With only Lo Current Power Supply on: > Requested power = .1 to 15w, power to load = 10w > I cycled DC power off/on: > Requested power = .1, power to load = .3w > Requested power = 10, power to load = 10 > I backed off requested power: > Requested power = .1, power to load = 10w > I turned Hi Current Power Supply on: > And raised requested power: > Requested power = 20w, power to load = 110w > Then backed off again: > Requested power = 9.5w, power to load = 10w > > Band Initial Power readings after I > raised > (Mtr) Power requested pwr past about 1w. > (With Hi and Lo Current Power Supplies on:) > 160-15 0 20, 110 > 12, 10 0 3, 25 > (With only the Lo Current Power Supply on:) > 160-15 0 10, 10 > 12, 10 0 3, 3 > (The lower power readings read when =< 10W requested, the higher power > readings read when > 10W requested and the Initial Power is what I > read just after switching bands) > > "HiCur" does flash on momentarily after switching bands. > There are no INFO ### messages. > > My equipment for this test: OHR WM-2 (QRP) and Heathkit HM-2140 (QRO) > watt meters and OHR RFL 100 and Heathkit Cantenna dummy loads. > > The testing steps during the KPA100 build checked out properly. I have > double checked the solder joints and reworked those that I thought might > have been questionable with no change in the (mis)behavior. I don't > know if these findings are of any help to you... I would be glad to > supply whatever readings as I may be able. > > Troubleshooting suggestions appreciated! > > Thanks, > Ed - AD7GR > K2 #6050 > > _______________________________________________ > 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 > > 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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Don,
You were spot on. The SWR Bridge diodes D16 and D17 had failed. The diodes arrived today in the mail, I replaced them and my K2 is up. Thank you very much for your help. 73, Ed - AD7GR K2 #6050 Don Wilhelm wrote: > Lack of power control with the KPA100 installed normally points to a > failure of the KPA100 wattmeter circuit. > > Start with replacing the 1N5711 diodes D16 and D17... > > If your KPA100 was working at one time and there is *any* possibility > that you encountered a lightning surge, then D16 and D17 are the most > likely suspects. _______________________________________________ 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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Ed,
For the future, consider your antenna situation carefully. When the station is not operational, all my antennas are grounded (via relays) and the K2 is connected to a dummy load. I do have an extensive antenna switching system here (not yet complete, but almost there) which relies on the Elecraft KRC2 along with remote relays to select the antenna to be used for each band - yours may be less complex, but consider a switching system to ground the antennas not in use and connect the K2 to a ground (or better a dummy load) when the K2 is not powered on. 73, Don W3FPR eKotz wrote: > Don, > > You were spot on. The SWR Bridge diodes D16 and D17 had failed. The > diodes arrived today in the mail, I replaced them and my K2 is up. > Thank you very much for your help. > > 73, > Ed - AD7GR > K2 #6050 > > > > Don Wilhelm wrote: >> Lack of power control with the KPA100 installed normally points to a >> failure of the KPA100 wattmeter circuit. >> >> Start with replacing the 1N5711 diodes D16 and D17... >> >> If your KPA100 was working at one time and there is *any* possibility >> that you encountered a lightning surge, then D16 and D17 are the most >> likely suspects. > _______________________________________________ > 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 > > 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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Don,
I am going to be installing a simpler antenna switching system here. Mine will be keyed off of the 12v power supply. When it is turned off, the antennas on my two operating positions will be switched from rigs to ground. The relays will be located outside in a weather proof box attached to 8' ground rods. My only problem is choosing the spdt relays. May I ask what type and brand of relays are you using? John [K7SVV] ----- Original Message ----- From: "Don Wilhelm" <[hidden email]> To: "eKotz" <[hidden email]> Cc: <[hidden email]>; <[hidden email]> Sent: Monday, June 18, 2007 8:43 PM Subject: Re: [Elecraft] KPA100 Power Malfunction > Ed, > > For the future, consider your antenna situation carefully. When the > station is not operational, all my antennas are grounded (via relays) and > the K2 is connected to a dummy load. I do have an extensive antenna > switching system here (not yet complete, but almost there) which relies on > the Elecraft KRC2 along with remote relays to select the antenna to be > used for each band - yours may be less complex, but consider a switching > system to ground the antennas not in use and connect the K2 to a ground > (or better a dummy load) when the K2 is not powered on. > > 73, > Don W3FPR > > eKotz wrote: >> Don, >> >> You were spot on. The SWR Bridge diodes D16 and D17 had failed. The >> diodes arrived today in the mail, I replaced them and my K2 is up. >> Thank you very much for your help. >> >> 73, >> Ed - AD7GR >> K2 #6050 >> >> >> >> Don Wilhelm wrote: >>> Lack of power control with the KPA100 installed normally points to a >>> failure of the KPA100 wattmeter circuit. >>> >>> Start with replacing the 1N5711 diodes D16 and D17... >>> >>> If your KPA100 was working at one time and there is *any* possibility >>> that you encountered a lightning surge, then D16 and D17 are the most >>> likely suspects. >> _______________________________________________ >> 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 >> >> > _______________________________________________ > 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: 7.5.472 / Virus Database: > 269.9.0/852 - Release Date: 6/17/2007 8:23 AM > > _______________________________________________ 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,
I am using the 6 position antenna relay design that appeared in QST a couple years back by Bill Smith (call?). FAR Circuits has a board and the 12 volt relays are American Zettler, Inc. AZ755-1C-12DE. You may want to search for the original article, it had ARRL test data on the SWR and loss and there was some information about where you could obtain the relays without encountering a high minimum order. I did order 24 of them for my purposes, and used the 24 volt relays, but your situation would likely use the 12 volt version. 73, Don W3FPR John [K7SVV] wrote: > Don, > I am going to be installing a simpler antenna switching system > here. Mine will be keyed off of the 12v power supply. When it is turned > off, the antennas on my two operating positions will be switched from > rigs to ground. The relays will be located outside in a weather proof > box attached to 8' ground rods. My only problem is choosing the spdt > relays. May I ask what type and brand of relays are you using? > > John [K7SVV] > > ----- Original Message ----- From: "Don Wilhelm" <[hidden email]> > To: "eKotz" <[hidden email]> > Cc: <[hidden email]>; <[hidden email]> > Sent: Monday, June 18, 2007 8:43 PM > Subject: Re: [Elecraft] KPA100 Power Malfunction > > >> Ed, >> >> For the future, consider your antenna situation carefully. When the >> station is not operational, all my antennas are grounded (via relays) >> and the K2 is connected to a dummy load. I do have an extensive >> antenna switching system here (not yet complete, but almost there) >> which relies on the Elecraft KRC2 along with remote relays to select >> the antenna to be used for each band - yours may be less complex, but >> consider a switching system to ground the antennas not in use and >> connect the K2 to a ground (or better a dummy load) when the K2 is not >> powered on. >> >> 73, >> Don W3FPR >> >> eKotz wrote: >>> Don, >>> >>> You were spot on. The SWR Bridge diodes D16 and D17 had failed. >>> The diodes arrived today in the mail, I replaced them and my K2 is >>> up. Thank you very much for your help. >>> >>> 73, >>> Ed - AD7GR >>> K2 #6050 >>> >>> >>> >>> Don Wilhelm wrote: >>>> Lack of power control with the KPA100 installed normally points to a >>>> failure of the KPA100 wattmeter circuit. >>>> >>>> Start with replacing the 1N5711 diodes D16 and D17... >>>> >>>> If your KPA100 was working at one time and there is *any* >>>> possibility that you encountered a lightning surge, then D16 and D17 >>>> are the most likely suspects. >>> _______________________________________________ >>> 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 >>> >>> >> _______________________________________________ >> 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: 7.5.472 / Virus Database: >> 269.9.0/852 - Release Date: 6/17/2007 8:23 AM >> >> > > > 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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> I am using the 6 position antenna relay design that appeared in QST a
> couple years back by Bill Smith (call?). FAR Circuits has a board and the > 12 volt relays are American Zettler, Inc. AZ755-1C-12DE. QST, April 2005, KO4NR Bill Smith. I've ordered a bunch of Far Circuit PCB's for me and a friend and built two of these myself. Works just fine even up to 1kW @ 30MHz. If anyone needs the article in PDF (1.6MB), drop me a line. 73 de Franki ON5ZO _______________________________________________ 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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