Re: [Elecraft] K3 losing RF
Paul, look for voltage drop at the power poles. Solder or crimping is critical and proper assembly is as well. A fraction of an ohm will cause an unworkable voltage drop. Look at the internal volt meter on the K3 display to identify excess voltage drop at the connection. Willis 'Cookie' Cooke K5EWJ From: Paul Ormandy ZL4PW zl...@orcon.net.nz To: elecraft@mailman.qth.net Sent: Sat, January 1, 2011 11:22:39 PM Subject: [Elecraft] K3 losing RF Hi all, My K3 has developed a problem... Power output is down to 70W and the LCD back-light flickers on tx. The Low Voltage message flicked up briefly once. I suspect a DC power problem but so saying, the voltage at the rig is 13.9V on transmit at 70W and the rig is drawing 13A. The problem seems worse on the 6mb. If I reduce the output RF control to around 60W, there is no perceptible LCD flickering. I will obtain another 20A power supply tomorrow and see if the problem persists. In the mean time, (apart from running low power), can anyone suggest what I should start looking for internally? Kind regards, Paul -- Paul Ormandy ZL4PW ZM4M www.radiodx.com www.zl4pw.orcon.net.nz __ 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] K3 losing RF - problem solved
Hi all, I was less flustered today and did some more checking... Discovered the main fuse in the negative supply line from the PSU had blown. I would like to know what reason it could have blown and at this point, presume it was something to do with running 100W on 6M. Thanks to all who e-mailed directly with suggestions. Cheers, Paul *From:* Paul Ormandy ZL4PW zl...@orcon.net.nz *To:* elecraft@mailman.qth.net *Sent:* Sat, January 1, 2011 11:22:39 PM *Subject:* [Elecraft] K3 losing RF Hi all, My K3 has developed a problem... Power output is down to 70W and the LCD back-light flickers on tx. The Low Voltage message flicked up briefly once. I suspect a DC power problem but so saying, the voltage at the rig is 13.9V on transmit at 70W and the rig is drawing 13A. The problem seems worse on the 6mb. If I reduce the output RF control to around 60W, there is no perceptible LCD flickering. I will obtain another 20A power supply tomorrow and see if the problem persists. In the mean time, (apart from running low power), can anyone suggest what I should start looking for internally? Kind regards, Paul -- Paul Ormandy ZL4PW ZM4M www.radiodx.com http://www.radiodx.com/ www.zl4pw.orcon.net.nz http://www.zl4pw.orcon.net.nz/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net 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 -- Paul Ormandy ZL4PW ZM4M www.radiodx.com www.zl4pw.orcon.net.nz __ 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] K3 losing RF
Hi all, My K3 has developed a problem... Power output is down to 70W and the LCD back-light flickers on tx. The Low Voltage message flicked up briefly once. I suspect a DC power problem but so saying, the voltage at the rig is 13.9V on transmit at 70W and the rig is drawing 13A. The problem seems worse on the 6mb. If I reduce the output RF control to around 60W, there is no perceptible LCD flickering. I will obtain another 20A power supply tomorrow and see if the problem persists. In the mean time, (apart from running low power), can anyone suggest what I should start looking for internally? Kind regards, Paul -- Paul Ormandy ZL4PW ZM4M www.radiodx.com www.zl4pw.orcon.net.nz __ 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] K3 losing RF power
Hi all, More info... Was unaware of the power recommendations on 50MHz... I was running 100W calling CQ on 50MHz when the problem suddenly arose. Maybe running 100W on 6M has been the cause? If I dial up 100W on any band, RF power as indicated on the K3 display is 70W. I am unable to get more than 70W on any band... And running very latest software 4.22. Cheers, Paul Hi all, My K3 has developed a problem... Power output is down to 70W and the LCD back-light flickers on tx. The Low Voltage message flicked up briefly once. I suspect a DC power problem but so saying, the voltage at the rig is 13.9V on transmit at 70W and the rig is drawing 13A. The problem seems worse on the 6mb. If I reduce the output RF control to around 60W, there is no perceptible LCD flickering. I will obtain another 20A power supply tomorrow and see if the problem persists. In the mean time, (apart from running low power), can anyone suggest what I should start looking for internally? Kind regards, Paul -- Paul Ormandy ZL4PW ZM4M www.radiodx.com www.zl4pw.orcon.net.nz __ 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] K3 losing RF power
Paul, It sounds to me like you have a voltage drop issue on transmit. Have you checked your power supplies voltage under load and the supply leads to the radio? That's where I'd be starting to look first. Jeff Cochrane - VK4BOF Innisfail, QLD, Australia Elecraft K3# 4257 - Original Message - From: Paul Ormandy ZL4PW To: elecraft@mailman.qth.net Sent: Sunday, January 02, 2011 4:22 PM Subject: [Elecraft] K3 losing RF power Hi all, More info... Was unaware of the power recommendations on 50MHz... I was running 100W calling CQ on 50MHz when the problem suddenly arose. Maybe running 100W on 6M has been the cause? If I dial up 100W on any band, RF power as indicated on the K3 display is 70W. I am unable to get more than 70W on any band... And running very latest software 4.22. Cheers, Paul Hi all, My K3 has developed a problem... Power output is down to 70W and the LCD back-light flickers on tx. The Low Voltage message flicked up briefly once. I suspect a DC power problem but so saying, the voltage at the rig is 13.9V on transmit at 70W and the rig is drawing 13A. The problem seems worse on the 6mb. If I reduce the output RF control to around 60W, there is no perceptible LCD flickering. I will obtain another 20A power supply tomorrow and see if the problem persists. In the mean time, (apart from running low power), can anyone suggest what I should start looking for internally? Kind regards, Paul -- Paul Ormandy ZL4PW ZM4M www.radiodx.com www.zl4pw.orcon.net.nz __ 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
