Has anyone experienced this problem, or know if I
should troubleshoot the bias, input, or output circuitry. All is well with the low power bypass path, and rig seems to work up to around 25 watts output. --- Curt Milton <[hidden email]> wrote: > Date: Sun, 27 May 2007 12:08:40 -0700 (PDT) > From: Curt Milton <[hidden email]> > To: [hidden email] > Subject: [Elecraft] KPA100 Failing to Produce High > Power > > All has been well up until now, including setting > the > bias per instructions. Without PA's my bias current > was 330 mA, so I successfully set it for 730 mA with > the PA's. > > I had adjusted R26 for 5w and got the VSWR sensor > zeroed. During my high power test (into a matched > antenna on a clear channel into a good antenna) my > VSWR is reading 1.2 on the K2 and similar on my > external meter. When I transmit the PA devices do > get > very hot (too hot to touch after about 10 seconds) > but > they quickly cool (maybe around 5 seconds or less) > after transmit ceases. > > Here is the behavior i am getting. First column is > K2 > power setting (on 20m), second is what the K2 reads > on > transmit, and third is my meter. My meter is not > state of the art but it is reasonable with my other > rig. > > K2 Setting K2 Indicated Meter > > 15 15 20 > 20 20 28 > 25 25 30 > 30 23 28 > 35 22 30 > 40 22 35 > 50 23 32 > > Thinking that maybe R26 was way off, i set the K2 > for > 40 watts and tried to adjust R26 to read 40 watts - > no > this got me no where. > > I tried to operate on different bands with two > different antennas. Same impact on all bands, > except > it has even lower output on 10m. > > Troubleshooting suggestions appreciated! > > 73, Curt ____________________________________________________________________________________ Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. http://videogames.yahoo.com/platform?platform=120121 _______________________________________________ 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 |
I did some additional troubleshooting, but maybe there
is nothing unusual in these bias measurements? Bias Rx Tx D11 13.7 0.7 D12 0.7 129 D13 13.7 0.2 D14 0.7 129 Q1/2 base 0 0.6 Still puzzled as why rig is limited to around 20w output. Current draw is proportional to RF power output, as above 20w setting rig will neither draw additional current nor output additional power. --- Curt Milton <[hidden email]> wrote: > Has anyone experienced this problem, or know if I > should troubleshoot the bias, input, or output > circuitry. All is well with the low power bypass > path, and rig seems to work up to around 25 watts > output. > --- Curt Milton <[hidden email]> wrote: > > > Date: Sun, 27 May 2007 12:08:40 -0700 (PDT) > > From: Curt Milton <[hidden email]> > > To: [hidden email] > > Subject: [Elecraft] KPA100 Failing to Produce High > > Power > > > > All has been well up until now, including setting > > the > > bias per instructions. Without PA's my bias > current > > was 330 mA, so I successfully set it for 730 mA > with > > the PA's. > > > > I had adjusted R26 for 5w and got the VSWR sensor > > zeroed. During my high power test (into a matched > > antenna on a clear channel into a good antenna) my > > VSWR is reading 1.2 on the K2 and similar on my > > external meter. When I transmit the PA devices do > > get > > very hot (too hot to touch after about 10 seconds) > > but > > they quickly cool (maybe around 5 seconds or less) > > after transmit ceases. > > > > Here is the behavior i am getting. First column > is > > K2 > > power setting (on 20m), second is what the K2 > reads > > on > > transmit, and third is my meter. My meter is not > > state of the art but it is reasonable with my > other > > rig. > > > > K2 Setting K2 Indicated Meter > > > > 15 15 20 > > 20 20 28 > > 25 25 30 > > 30 23 28 > > 35 22 30 > > 40 22 35 > > 50 23 32 > > > > Thinking that maybe R26 was way off, i set the K2 > > for > > 40 watts and tried to adjust R26 to read 40 watts > - > > no > > this got me no where. > > > > I tried to operate on different bands with two > > different antennas. Same impact on all bands, > > except > > it has even lower output on 10m. > > > > Troubleshooting suggestions appreciated! > > > > 73, Curt > > > > > > Be a PS3 game guru. > Get your game face on with the latest PS3 news and > previews at Yahoo! Games. > http://videogames.yahoo.com/platform?platform=120121 > _______________________________________________ > 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 > ____________________________________________________________________________________Ready for the edge of your seat? Check out tonight's top picks on Yahoo! TV. http://tv.yahoo.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 |
In reply to this post by Curt Milton
Curt:
I bet you are using the KPA100 with a KAT100 and using the tune button on the front panel of the K2. When the KPA100 is connected the output power of the KPA100 is limited to 20 watts. Try plugging a key into the key jack and set it for Hand Key mode and press the key. I bet you will see the amount of power out that you have set with the power control on the front panel of the K2. If this is the case I fought the same thing for a day before I realized that the K2 firmware limits the power out to 20 watts in the tune mode when a KAT100 is connected. -------------- Original message -------------- From: Curt Milton <[hidden email]> > I did some additional troubleshooting, but maybe there > is nothing unusual in these bias measurements? > > Bias Rx Tx > D11 13.7 0.7 > D12 0.7 129 > D13 13.7 0.2 > D14 0.7 129 > Q1/2 base 0 0.6 > > Still puzzled as why rig is limited to around 20w > output. Current draw is proportional to RF power > output, as above 20w setting rig will neither draw > additional current nor output additional power. > > --- Curt Milton wrote: > > > Has anyone experienced this problem, or know if I > > should troubleshoot the bias, input, or output > > circuitry. All is well with the low power bypass > > path, and rig seems to work up to around 25 watts > > output. > > --- Curt Milton wrote: > > > > > Date: Sun, 27 May 2007 12:08:40 -0700 (PDT) > > > From: Curt Milton > > > To: [hidden email] > > > Subject: [Elecraft] KPA100 Failing to Produce High > > > Power > > > > > > All has been well up until now, including setting > > > the > > > bias per instructions. Without PA's my bias > > current > > > was 330 mA, so I successfully set it for 730 mA > > with > > > the PA's. > > > > > > I had adjusted R26 for 5w and got the VSWR sensor > > > zeroed. During my high power test (into a matched > > > antenna on a clear channel into a good antenna) my > > > VSWR is reading 1.2 on the K2 and similar on my > > > external meter. When I transmit the PA devices do > > > get > > > very hot (too hot to touch after about 10 seconds) > > > but > > > they quickly cool (maybe around 5 seconds or less) > > > after transmit ceases. > > > > > > Here is the behavior i am getting. First column > > is > > > K2 > > > power setting (on 20m), second is what the K2 > > reads > > > on > > > transmit, and third is my meter. My meter is not > > > state of the art but it is reasonable with my > > other > > > rig. > > > > > > K2 Setting K2 Indicated Meter > > > > > > 15 15 20 > > > 20 20 28 > > > 25 25 30 > > > 30 23 28 > > > 35 22 30 > > > 40 22 35 > > > 50 23 32 > > > > > > Thinking that maybe R26 was way off, i set the K2 > > > for > > > 40 watts and tried to adjust R26 to read 40 watts > > - > > > no > > > this got me no where. > > > > > > I tried to operate on different bands with two > > > different antennas. Same impact on all bands, > > > except > > > it has even lower output on 10m. > > > > > > Troubleshooting suggestions appreciated! > > > > > > 73, Curt > > > > > > > > > > > ________________________________________________________________________________ > ____ > > Be a PS3 game guru. > > Get your game face on with the latest PS3 news and > > previews at Yahoo! Games. > > http://videogames.yahoo.com/platform?platform=120121 > > _______________________________________________ > > 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 > > > > > > > ________________________________________________________________________________ > ____Ready for the edge of your seat? > Check out tonight's top picks on Yahoo! TV. > http://tv.yahoo.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 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 |
In reply to this post by Curt Milton
Curt,
How are you attempting to initiate transmit? If you ae pressing TUNE, then 20 watts is what should be produced - the KPA100 firmware limits TUNE to 20 watts. If you need to try at a higher power than that, you must press TUNE and DISPLAY together. OTOH, if you are already doing TUNE/DISPLAY, then check the KPA100 LPF toroids for the correct number of turns - count the nmber of times the wire passes through the center of the core. 73, Don W3FPR Curt Milton wrote: > I did some additional troubleshooting, but maybe there > is nothing unusual in these bias measurements? > > Bias Rx Tx > D11 13.7 0.7 > D12 0.7 129 > D13 13.7 0.2 > D14 0.7 129 > Q1/2 base 0 0.6 > > Still puzzled as why rig is limited to around 20w > output. Current draw is proportional to RF power > output, as above 20w setting rig will neither draw > additional current nor output additional power. > > --- Curt Milton <[hidden email]> wrote: > >> Has anyone experienced this problem, or know if I >> should troubleshoot the bias, input, or output >> circuitry. All is well with the low power bypass >> path, and rig seems to work up to around 25 watts >> output. >> --- Curt Milton <[hidden email]> wrote: >> >>> Date: Sun, 27 May 2007 12:08:40 -0700 (PDT) >>> From: Curt Milton <[hidden email]> >>> To: [hidden email] >>> Subject: [Elecraft] KPA100 Failing to Produce High >>> Power >>> >>> All has been well up until now, including setting >>> the >>> bias per instructions. Without PA's my bias >> current >>> was 330 mA, so I successfully set it for 730 mA >> with >>> the PA's. >>> >>> I had adjusted R26 for 5w and got the VSWR sensor >>> zeroed. During my high power test (into a matched >>> antenna on a clear channel into a good antenna) my >>> VSWR is reading 1.2 on the K2 and similar on my >>> external meter. When I transmit the PA devices do >>> get >>> very hot (too hot to touch after about 10 seconds) >>> but >>> they quickly cool (maybe around 5 seconds or less) >>> after transmit ceases. >>> >>> Here is the behavior i am getting. First column >> is >>> K2 >>> power setting (on 20m), second is what the K2 >> reads >>> on >>> transmit, and third is my meter. My meter is not >>> state of the art but it is reasonable with my >> other >>> rig. >>> >>> K2 Setting K2 Indicated Meter >>> >>> 15 15 20 >>> 20 20 28 >>> 25 25 30 >>> 30 23 28 >>> 35 22 30 >>> 40 22 35 >>> 50 23 32 >>> >>> Thinking that maybe R26 was way off, i set the K2 >>> for >>> 40 watts and tried to adjust R26 to read 40 watts >> - >>> no >>> this got me no where. >>> >>> I tried to operate on different bands with two >>> different antennas. Same impact on all bands, >>> except >>> it has even lower output on 10m. >>> >>> Troubleshooting suggestions appreciated! >>> >>> 73, Curt >> >> >> >> > ____________________________________________________________________________________ >> Be a PS3 game guru. >> Get your game face on with the latest PS3 news and >> previews at Yahoo! Games. >> http://videogames.yahoo.com/platform?platform=120121 >> _______________________________________________ >> 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 >> > > > > > ____________________________________________________________________________________Ready for the edge of your seat? > Check out tonight's top picks on Yahoo! TV. > http://tv.yahoo.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 > 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 |
Or simply move the POWER control, and the output should jump to whatever
corresponds to the position of the POWER control up to the full 100 watts, even in TUNE mode. Ron AC7AC -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Don Wilhelm Sent: Thursday, May 31, 2007 4:14 PM To: Curt Milton Cc: [hidden email] Subject: Re: Fwd: [Elecraft] KPA100 Failing to Produce High Power Curt, How are you attempting to initiate transmit? If you ae pressing TUNE, then 20 watts is what should be produced - the KPA100 firmware limits TUNE to 20 watts. If you need to try at a higher power than that, you must press TUNE and DISPLAY together. OTOH, if you are already doing TUNE/DISPLAY, then check the KPA100 LPF toroids for the correct number of turns - count the nmber of times the wire passes through the center of the core. 73, Don W3FPR _______________________________________________ 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 |
In reply to this post by Don Wilhelm-3
Don and others who responded - thanks!
(1) its hard to fix what isn't broke (2) i have been using this rig many years .... (3) somehow i falsely believed i could tweak the power knob BEFORE hitting TUNE (4) maybe i hard time believing i assembled this board without any issues! (5) the two button routine to transmit full power is actually nifty ! my rig does produce 100 watts! i do notice the finals are too hot to touch when transmitting, but they cool in a few seconds when transmit ceases. maybe this is normal (i have never touched an operational 50 watt device before). i guess i need to find where the K2 will tell me its temperature to see if all is well. 73, curt --- Don Wilhelm <[hidden email]> wrote: > Curt, > > How are you attempting to initiate transmit? If you > ae pressing TUNE, > then 20 watts is what should be produced - the > KPA100 firmware limits > TUNE to 20 watts. If you need to try at a higher > power than that, you > must press TUNE and DISPLAY together. > > OTOH, if you are already doing TUNE/DISPLAY, then > check the KPA100 LPF > toroids for the correct number of turns - count the > nmber of times the > wire passes through the center of the core. > > 73, > Don W3FPR > > Curt Milton wrote: > > I did some additional troubleshooting, but maybe > there > > is nothing unusual in these bias measurements? > > > > Bias Rx Tx > > D11 13.7 0.7 > > D12 0.7 129 > > D13 13.7 0.2 > > D14 0.7 129 > > Q1/2 base 0 0.6 > > > > Still puzzled as why rig is limited to around 20w > > output. Current draw is proportional to RF power > > output, as above 20w setting rig will neither draw > > additional current nor output additional power. > > > > --- Curt Milton <[hidden email]> wrote: > > > >> Has anyone experienced this problem, or know if I > >> should troubleshoot the bias, input, or output > >> circuitry. All is well with the low power bypass > >> path, and rig seems to work up to around 25 watts > >> output. > >> --- Curt Milton <[hidden email]> wrote: > >> > >>> Date: Sun, 27 May 2007 12:08:40 -0700 (PDT) > >>> From: Curt Milton <[hidden email]> > >>> To: [hidden email] > >>> Subject: [Elecraft] KPA100 Failing to Produce > High > >>> Power > >>> > >>> All has been well up until now, including > setting > >>> the > >>> bias per instructions. Without PA's my bias > >> current > >>> was 330 mA, so I successfully set it for 730 mA > >> with > >>> the PA's. > >>> > >>> I had adjusted R26 for 5w and got the VSWR > sensor > >>> zeroed. During my high power test (into a > matched > >>> antenna on a clear channel into a good antenna) > my > >>> VSWR is reading 1.2 on the K2 and similar on my > >>> external meter. When I transmit the PA devices > do > >>> get > >>> very hot (too hot to touch after about 10 > seconds) > >>> but > >>> they quickly cool (maybe around 5 seconds or > less) > >>> after transmit ceases. > >>> > >>> Here is the behavior i am getting. First column > >> is > >>> K2 > >>> power setting (on 20m), second is what the K2 > >> reads > >>> on > >>> transmit, and third is my meter. My meter is > not > >>> state of the art but it is reasonable with my > >> other > >>> rig. > >>> > >>> K2 Setting K2 Indicated Meter > >>> > >>> 15 15 20 > >>> 20 20 28 > >>> 25 25 30 > >>> 30 23 28 > >>> 35 22 30 > >>> 40 22 35 > >>> 50 23 32 > >>> > >>> Thinking that maybe R26 was way off, i set the > K2 > >>> for > >>> 40 watts and tried to adjust R26 to read 40 > watts > >> - > >>> no > >>> this got me no where. > >>> > >>> I tried to operate on different bands with two > >>> different antennas. Same impact on all bands, > >>> except > >>> it has even lower output on 10m. > >>> > >>> Troubleshooting suggestions appreciated! > >>> > >>> 73, Curt > >> > >> > >> > >> > > > > >> Be a PS3 game guru. > >> Get your game face on with the latest PS3 news > and > >> previews at Yahoo! Games. > >> > http://videogames.yahoo.com/platform?platform=120121 > >> _______________________________________________ > >> 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 > >> > > > > > > > > > > > > for the edge of your seat? > > Check out tonight's top picks on Yahoo! TV. > > http://tv.yahoo.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 > > > ____________________________________________________________________________________ Need a vacation? Get great deals to amazing places on Yahoo! Travel. http://travel.yahoo.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 |
Curt,
If you are transmitting full key-down for more than a few seconds (as with digital modes), you should limit the power to 35 watts. The CAL TPA menu will provide a reference for when the fan turns on - be certain you have it set correctly - allow everything to cool to room temperature (at least 1 hour) and then set the CAL TPA parameter to correspond with the room temperature in degrees Celcius. If you have not snugged down the mounting screws for the PA output transistors yet, please do that to assure that they have adequate contact with the heat sink. Yes, the PA transistors will be hot to the touch after a few seconds of keydown - but SSB and CW are intermittent modes, and full power is normally only present for brief periods. The KPA100 watt rating is only valid for CW and SSB modes, for other contiuous duty modes, 35 watts is the recommended maximum power. 73, Don W3FPR Curt Milton wrote: > > i do notice the finals are too hot to touch when > transmitting, but they cool in a few seconds when > transmit ceases. maybe this is normal (i have never > touched an operational 50 watt device before). i > guess i need to find where the K2 will tell me its > temperature to see if all is well. > > 73, curt _______________________________________________ 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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