Re: [Elecraft] Fwd: AW: K3 KPA3 bias adjust
This is interesting. When I measure the current of my early K3 #00345 using the internal display I see only a small difference when in TX at 10W or 100W power setting. Both are in the region of 2.25/2.35A TX (1.22A RX) with the internal measured voltage RX 14.1V TX 14.0V. Question is does the KPA3 have bypass mode bias control? No change if in TX test mode, ensuring no output. The bypass relay operates and the power display scales correctly with change over Hi/Lo power. These numbers compare with the PSU current meter. Anyone else seeing this? Has something gone missing with a firmware upgrade? Regards, Mike VP8NO On 07/03/2019 16:03, Bob McGraw K4TAX wrote: I just looked at the current values of my K3s using the internal DISP current and voltage values. This is how it came from the factory after replacement of the KPA3A rev E amp on 5/30/2018. In RX USB mode = 1.6A Vcc = 13.8V Audio volume at minimum. In TX USB mode no audio, 10 watt PWR setting = 1.60A In TX USB mode no audio, 100 watt PWR setting = 2.91A The PWR delta is 1.31 amps In RX CW mode, = 1.03A Vcc 13.8V Audio volume at minimum. In TX CW mode PTT closed, key open, 10 watt PWR setting 1.54A Vcc 13.7V In TX XW mode, PTT closed, key open, 100 watt PWR setting 2.85A Vcc 13.6V The PWR delta is 1.31 amps Your values may be different if you have the 2nd receiver and can vary depending on your Vcc. 73 Bob, K4TAX __ 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] Fwd: AW: K3 KPA3 bias adjust
I just looked at the current values of my K3s using the internal DISP current and voltage values. This is how it came from the factory after replacement of the KPA3A rev E amp on 5/30/2018. In RX USB mode = 1.6A Vcc = 13.8V Audio volume at minimum. In TX USB mode no audio, 10 watt PWR setting = 1.60A In TX USB mode no audio, 100 watt PWR setting = 2.91A The PWR delta is 1.31 amps In RX CW mode, = 1.03A Vcc 13.8V Audio volume at minimum. In TX CW mode PTT closed, key open, 10 watt PWR setting 1.54A Vcc 13.7V In TX XW mode, PTT closed, key open, 100 watt PWR setting 2.85A Vcc 13.6V The PWR delta is 1.31 amps Your values may be different if you have the 2nd receiver and can vary depending on your Vcc. 73 Bob, K4TAX On 3/7/2019 12:34 PM, hawley, charles j jr wrote: Could you be mistaken on my procedure? The 1 amp plus or minus is typical with three K3s es that I know of. There are two devices and two trim pots. This instruction is only for one device since he says "the BIAS pot" I believe... " If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum." I am looking at the total current accessible from DISP and read out on the front panel. First I go to the LPA only, read the total current drawn by the rig under XMIT SSB(no modulation) and then engage the KPA by turning up the power knob and I subtract the first reading from the second. I get about 1.05 amps. Am I close to knowing the total current into the KPA this way? I feel that this important knowledge about how to set up the amp is fuzzy or not well known...the why I asked the question. Thanks for the replies!! Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: Don Wilhelm Sent: Thursday, March 7, 2019 12:10 PM To: hawley, charles j jr; elecraft@mailman.qth.net; Mike Harris Subject: Re: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Chuck, The instruction cited was for a 400-500 ma rise TOTAL (not per device). So I conclude your bias is set too high or there is a problem in the bias circuit. 73, Don W3FPR On 3/7/2019 9:31 AM, hawley, charles j jr wrote: Thanks for the info. Using xmit for the low power amp and then going to the high power amp shows a difference of 1.05A. So my devices are showing about 500+ ma each. In the ball park. Thanks so much for the reply. Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: elecraft-boun...@mailman.qth.net on behalf of Mike Harris via Elecraft Sent: Thursday, March 7, 2019 5:43 AM To: elecraft@mailman.qth.net Subject: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Hi, Forwarded a 2009 email exchange for your info. I have NOT tried this so use with care and at your own risk. Regards, Mike VP8NO Forwarded Message Subject: AW: [Elecraft] K3 KPA3 bias adjust Date: Sat, 3 Jan 2009 19:46:55 +0100 From: Koppendorfer Klaus To: Jan Erik Holm CC: Elecraft@mailman.qth.net Locate the BIAS pot at the front of the KPA3, between the heat sink and the KPA3 shield. Note what the display current is in the VFO B readout when you tap the Display button and turn the VFO B knob to the current readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should be about 1.90 to 2.0A when the Power knob is set to 12w or above so the KPA3 is made active (but there is no RF output since XMIT is used). Or you can press the PTT button but do not speak. If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum. __ 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 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] Fwd: AW: K3 KPA3 bias adjust
Chuck, True, but make sure that current is being distributed equally between the 2 devices. Set both pots to full CCW and then adjust one for a 400-500ma rise, then adjust the other for another 400-500ma rise. You should then have a 1 amp rise total, but you will be assured that each device is drawing the proper amount of idle current. 73, Don W3FPR On 3/7/2019 1:34 PM, hawley, charles j jr wrote: Could you be mistaken on my procedure? The 1 amp plus or minus is typical with three K3s es that I know of. There are two devices and two trim pots. This instruction is only for one device since he says "the BIAS pot" I believe... "If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum." I am looking at the total current accessible from DISP and read out on the front panel. First I go to the LPA only, read the total current drawn by the rig under XMIT SSB(no modulation) and then engage the KPA by turning up the power knob and I subtract the first reading from the second. I get about 1.05 amps. Am I close to knowing the total current into the KPA this way? I feel that this important knowledge about how to set up the amp is fuzzy or not well known...the why I asked the question. Thanks for the replies!! Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles *From:* Don Wilhelm *Sent:* Thursday, March 7, 2019 12:10 PM *To:* hawley, charles j jr; elecraft@mailman.qth.net; Mike Harris *Subject:* Re: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Chuck, The instruction cited was for a 400-500 ma rise TOTAL (not per device). So I conclude your bias is set too high or there is a problem in the bias circuit. 73, Don W3FPR On 3/7/2019 9:31 AM, hawley, charles j jr wrote: > Thanks for the info. Using xmit for the low power amp and then going to the high power amp shows a difference of 1.05A. So my devices are showing about 500+ ma each. In the ball park. > Thanks so much for the reply. > > Chuck Hawley > c-haw...@illinois.edu > > Amateur Radio, KE9UW > aka Jack, BMW Motorcycles > > > From: elecraft-boun...@mailman.qth.net on behalf of Mike Harris via Elecraft > Sent: Thursday, March 7, 2019 5:43 AM > To: elecraft@mailman.qth.net > Subject: [Elecraft] Fwd: AW: K3 KPA3 bias adjust > > Hi, > > Forwarded a 2009 email exchange for your info. I have NOT tried this so > use with care and at your own risk. > > Regards, > > Mike VP8NO > > > Forwarded Message > Subject: AW: [Elecraft] K3 KPA3 bias adjust > Date: Sat, 3 Jan 2009 19:46:55 +0100 > From: Koppendorfer Klaus > To: Jan Erik Holm > CC: Elecraft@mailman.qth.net > > Locate the BIAS pot at the front of the KPA3, between the heat sink and > the KPA3 shield. Note what the display current is in the VFO B readout > when you tap the Display button and turn the VFO B knob to the current > readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should > be about 1.90 to 2.0A when the Power knob is set to 12w or above so the > KPA3 is made active (but there is no RF output since XMIT is used). Or > you can press the PTT button but do not speak. > > If there is much more current than this, set the BIAS pot to minimum > (fully counter clockwise). Then tap XMIT (not TUNE) and note what the > current is in VFO B's readout. Slowly turn up the BIAS pot until you see > 400-500mA more current that was seen with the BIAS pot at minimum. > __ 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] Fwd: AW: K3 KPA3 bias adjust
Could you be mistaken on my procedure? The 1 amp plus or minus is typical with three K3s es that I know of. There are two devices and two trim pots. This instruction is only for one device since he says "the BIAS pot" I believe... " If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum." I am looking at the total current accessible from DISP and read out on the front panel. First I go to the LPA only, read the total current drawn by the rig under XMIT SSB(no modulation) and then engage the KPA by turning up the power knob and I subtract the first reading from the second. I get about 1.05 amps. Am I close to knowing the total current into the KPA this way? I feel that this important knowledge about how to set up the amp is fuzzy or not well known...the why I asked the question. Thanks for the replies!! Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: Don Wilhelm Sent: Thursday, March 7, 2019 12:10 PM To: hawley, charles j jr; elecraft@mailman.qth.net; Mike Harris Subject: Re: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Chuck, The instruction cited was for a 400-500 ma rise TOTAL (not per device). So I conclude your bias is set too high or there is a problem in the bias circuit. 73, Don W3FPR On 3/7/2019 9:31 AM, hawley, charles j jr wrote: > Thanks for the info. Using xmit for the low power amp and then going to the > high power amp shows a difference of 1.05A. So my devices are showing about > 500+ ma each. In the ball park. > Thanks so much for the reply. > > Chuck Hawley > c-haw...@illinois.edu > > Amateur Radio, KE9UW > aka Jack, BMW Motorcycles > > > From: elecraft-boun...@mailman.qth.net on > behalf of Mike Harris via Elecraft > Sent: Thursday, March 7, 2019 5:43 AM > To: elecraft@mailman.qth.net > Subject: [Elecraft] Fwd: AW: K3 KPA3 bias adjust > > Hi, > > Forwarded a 2009 email exchange for your info. I have NOT tried this so > use with care and at your own risk. > > Regards, > > Mike VP8NO > > > Forwarded Message > Subject: AW: [Elecraft] K3 KPA3 bias adjust > Date: Sat, 3 Jan 2009 19:46:55 +0100 > From: Koppendorfer Klaus > To: Jan Erik Holm > CC: Elecraft@mailman.qth.net > > Locate the BIAS pot at the front of the KPA3, between the heat sink and > the KPA3 shield. Note what the display current is in the VFO B readout > when you tap the Display button and turn the VFO B knob to the current > readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should > be about 1.90 to 2.0A when the Power knob is set to 12w or above so the > KPA3 is made active (but there is no RF output since XMIT is used). Or > you can press the PTT button but do not speak. > > If there is much more current than this, set the BIAS pot to minimum > (fully counter clockwise). Then tap XMIT (not TUNE) and note what the > current is in VFO B's readout. Slowly turn up the BIAS pot until you see > 400-500mA more current that was seen with the BIAS pot at minimum. > __ 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] Fwd: AW: K3 KPA3 bias adjust
Chuck, The instruction cited was for a 400-500 ma rise TOTAL (not per device). So I conclude your bias is set too high or there is a problem in the bias circuit. 73, Don W3FPR On 3/7/2019 9:31 AM, hawley, charles j jr wrote: Thanks for the info. Using xmit for the low power amp and then going to the high power amp shows a difference of 1.05A. So my devices are showing about 500+ ma each. In the ball park. Thanks so much for the reply. Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: elecraft-boun...@mailman.qth.net on behalf of Mike Harris via Elecraft Sent: Thursday, March 7, 2019 5:43 AM To: elecraft@mailman.qth.net Subject: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Hi, Forwarded a 2009 email exchange for your info. I have NOT tried this so use with care and at your own risk. Regards, Mike VP8NO Forwarded Message Subject: AW: [Elecraft] K3 KPA3 bias adjust Date: Sat, 3 Jan 2009 19:46:55 +0100 From: Koppendorfer Klaus To: Jan Erik Holm CC: Elecraft@mailman.qth.net Locate the BIAS pot at the front of the KPA3, between the heat sink and the KPA3 shield. Note what the display current is in the VFO B readout when you tap the Display button and turn the VFO B knob to the current readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should be about 1.90 to 2.0A when the Power knob is set to 12w or above so the KPA3 is made active (but there is no RF output since XMIT is used). Or you can press the PTT button but do not speak. If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum. __ 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] Fwd: AW: K3 KPA3 bias adjust
Thanks for the info. Using xmit for the low power amp and then going to the high power amp shows a difference of 1.05A. So my devices are showing about 500+ ma each. In the ball park. Thanks so much for the reply. Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: elecraft-boun...@mailman.qth.net on behalf of Mike Harris via Elecraft Sent: Thursday, March 7, 2019 5:43 AM To: elecraft@mailman.qth.net Subject: [Elecraft] Fwd: AW: K3 KPA3 bias adjust Hi, Forwarded a 2009 email exchange for your info. I have NOT tried this so use with care and at your own risk. Regards, Mike VP8NO Forwarded Message Subject: AW: [Elecraft] K3 KPA3 bias adjust Date: Sat, 3 Jan 2009 19:46:55 +0100 From: Koppendorfer Klaus To: Jan Erik Holm CC: Elecraft@mailman.qth.net Locate the BIAS pot at the front of the KPA3, between the heat sink and the KPA3 shield. Note what the display current is in the VFO B readout when you tap the Display button and turn the VFO B knob to the current readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should be about 1.90 to 2.0A when the Power knob is set to 12w or above so the KPA3 is made active (but there is no RF output since XMIT is used). Or you can press the PTT button but do not speak. If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum. 73 OE6KYG KX1 244 K2 1331 K3 115 > -Ursprüngliche Nachricht- > Von: elecraft-boun...@mailman.qth.net [mailto:elecraft- > boun...@mailman.qth.net] Im Auftrag von Jan Erik Holm > Gesendet: Samstag, 03. Jänner 2009 19:35 > Cc: Elecraft@mailman.qth.net > Betreff: Re: [Elecraft] K3 KPA3 bias adjust > > Thanks Ron but I knew this already. > > Probably have to write to K3support and ask, > however I´m very surprised nobody could answer > on the reflector. > > Jim SM2EKM > -- > Ron D'Eau Claire wrote: > > Hello Jim: > > > > That pot, along with all the other trimmers in the K3, is adjusted at > the > > factory. There are specific cautions against touching any of them in the > > field; all field adjustments are done in firmware. > > > > If you have a problem with the KPA3, suggest you post a message to > > k3supp...@elecraft.com. If an adjustment is needed that can be done in > the > > field, one of the fellows there can give you specifics. > > > > Ron AC7AC > > > > > > > > -Original Message- > > From: elecraft-boun...@mailman.qth.net > > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jan Erik Holm > > Sent: Saturday, January 03, 2009 6:55 AM > > To: Elecraft@mailman.qth.net > > Subject: [Elecraft] K3 KPA3 bias adjust > > > > I find nothing about it in any manual. R11 on KPA3 > > I guess. What are the specifications for the bias > > adjust? > > > > 73 Jim SM2EKM __ 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 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] Fwd: AW: K3 KPA3 bias adjust
Hi, Forwarded a 2009 email exchange for your info. I have NOT tried this so use with care and at your own risk. Regards, Mike VP8NO Forwarded Message Subject: AW: [Elecraft] K3 KPA3 bias adjust Date: Sat, 3 Jan 2009 19:46:55 +0100 From: Koppendorfer Klaus To: Jan Erik Holm CC: Elecraft@mailman.qth.net Locate the BIAS pot at the front of the KPA3, between the heat sink and the KPA3 shield. Note what the display current is in the VFO B readout when you tap the Display button and turn the VFO B knob to the current readout. In RX, it should be 1.0A or so. In XMIT (not TUNE), it should be about 1.90 to 2.0A when the Power knob is set to 12w or above so the KPA3 is made active (but there is no RF output since XMIT is used). Or you can press the PTT button but do not speak. If there is much more current than this, set the BIAS pot to minimum (fully counter clockwise). Then tap XMIT (not TUNE) and note what the current is in VFO B's readout. Slowly turn up the BIAS pot until you see 400-500mA more current that was seen with the BIAS pot at minimum. 73 OE6KYG KX1 244 K2 1331 K3 115 -Ursprüngliche Nachricht- Von: elecraft-boun...@mailman.qth.net [mailto:elecraft- boun...@mailman.qth.net] Im Auftrag von Jan Erik Holm Gesendet: Samstag, 03. Jänner 2009 19:35 Cc: Elecraft@mailman.qth.net Betreff: Re: [Elecraft] K3 KPA3 bias adjust Thanks Ron but I knew this already. Probably have to write to K3support and ask, however I´m very surprised nobody could answer on the reflector. Jim SM2EKM -- Ron D'Eau Claire wrote: > Hello Jim: > > That pot, along with all the other trimmers in the K3, is adjusted at the > factory. There are specific cautions against touching any of them in the > field; all field adjustments are done in firmware. > > If you have a problem with the KPA3, suggest you post a message to > k3supp...@elecraft.com. If an adjustment is needed that can be done in the > field, one of the fellows there can give you specifics. > > Ron AC7AC > > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jan Erik Holm > Sent: Saturday, January 03, 2009 6:55 AM > To: Elecraft@mailman.qth.net > Subject: [Elecraft] K3 KPA3 bias adjust > > I find nothing about it in any manual. R11 on KPA3 > I guess. What are the specifications for the bias > adjust? > > 73 Jim SM2EKM __ 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
