[Elecraft] KPA-500 Failure
Hello Rick (NK7I) and Andy (K3WYC) - Tnx replies "Message: 17 Date: Wed, 24 Apr 2024 14:11:28 + From: Andy Durbin To: "elecraft@mailman.qth.net" Subject: [Elecraft] KPA-500 Failure Message-ID: < dm4pr10mb6791e0db00b79830385f5cd28c...@dm4pr10mb6791.namprd10.prod.outlook.com > Content-Type: text/plain; charset="iso-8859-1" "With the OPER light GREEN and slowly increasing the RF drive level to the amp, there is a point where an internal relay 'click' can be heard, the 50-watt LED on the top row of LEDs turns red and the FAULT light turns red." All the KPA500 LED are single color. The 50 W LED is either lit green or not lit. Did it appear to be red because of light leakage from the FAULT LED? Some quite detailed discussion of KPA500 failure modes on the groups.io forum: https://groups.io/g/KPA500/topics 73, Andy, k3wyc " IF I remember correctly, the entire top row of LEDs flashed red in color when the failure happened. After removing the top cover, the PA assy is visible but there appears to be no easy way access it due to a large bolt connecting the round transformer to the bottom plate. Will have to access the home-builder manual to figure out how to inspect the PA assembly. TU for the reply -- Dick/w7wkr __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KPA-500 Failure
"With the OPER light GREEN and slowly increasing the RF drive level to the amp, there is a point where an internal relay 'click' can be heard, the 50-watt LED on the top row of LEDs turns red and the FAULT light turns red." All the KPA500 LED are single color. The 50 W LED is either lit green or not lit. Did it appear to be red because of light leakage from the FAULT LED? Some quite detailed discussion of KPA500 failure modes on the groups.io forum: https://groups.io/g/KPA500/topics 73, Andy, k3wyc __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA-500 Failure
It sounds like blown FETs. It may be time to ship it to CA where any/all upgrades can be done as well as repair. They're a little backed up, so it may take a few weeks. Parts and shop time too of course. Call the techs to discuss it and get an RSA and ask if they want you to pull the transformer to save shipping weight/cost. You MUST have the RSA (write it on the box, a cover letter inside and with any email discussion once it's issued). The tech indicated that damage to the FETs may be cumulative over time, so it may not be THIS event. But it won't hurt to go through the entire antenna and feed system to be sure. Or you can dive in to repair it; if you feel qualified. Sorry, been there too. Rick nk7i On 4/23/2024 6:52 PM, Dick Bingham wrote: Greeting to everyone I have read the KPA500 operator manual in hopes of solving my issue and have found nothing that solves/fixes the problem. This amplifier has been a workhorse for many years and today after the KAT500 antenna tuner searched/found a 'match' for a new antenna, I selected OPER on the KPA500, and applied drive power to the amplifier. Immediately, the amplifier displayed a momentary overload indicated by the top row of LEDs (power indicator ones) all flashing ON after which, the amp FAULTED and shut down. The RF drive level was around 20-watts and should have provided about 300-watts output at the time this occurred. I tapped the OPER/STBY button and tried to activate the amplifier and found there is no response to incoming RF drive. I removed/reapplied 'mains' power, pressed the 'EDIT' and ON keys simultaneously to reset everything and that did not correct the problem. The power supply voltage is in spec so no issue there. With the OPER light GREEN and slowly increasing the RF drive level to the amp, there is a point where an internal relay 'click' can be heard, the 50-watt LED on the top row of LEDs turns red and the FAULT light turns red. I could not detect any sign of smoke (nose/eyes) so have not opened the case to look for burned parts. Before I open the 'case' and look for obvious problems, any observations or suggestions received here will be appreciated. Kinda looks like blown amp power FETs. Dick - w7wkr __ 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 Message delivered to rick.n...@gmail.com __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KPA-500 Failure
Greeting to everyone I have read the KPA500 operator manual in hopes of solving my issue and have found nothing that solves/fixes the problem. This amplifier has been a workhorse for many years and today after the KAT500 antenna tuner searched/found a 'match' for a new antenna, I selected OPER on the KPA500, and applied drive power to the amplifier. Immediately, the amplifier displayed a momentary overload indicated by the top row of LEDs (power indicator ones) all flashing ON after which, the amp FAULTED and shut down. The RF drive level was around 20-watts and should have provided about 300-watts output at the time this occurred. I tapped the OPER/STBY button and tried to activate the amplifier and found there is no response to incoming RF drive. I removed/reapplied 'mains' power, pressed the 'EDIT' and ON keys simultaneously to reset everything and that did not correct the problem. The power supply voltage is in spec so no issue there. With the OPER light GREEN and slowly increasing the RF drive level to the amp, there is a point where an internal relay 'click' can be heard, the 50-watt LED on the top row of LEDs turns red and the FAULT light turns red. I could not detect any sign of smoke (nose/eyes) so have not opened the case to look for burned parts. Before I open the 'case' and look for obvious problems, any observations or suggestions received here will be appreciated. Kinda looks like blown amp power FETs. Dick - w7wkr __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KPA-500 failure
Anyone else have their KPA-500 crash on power ON? All LED's briefly flash then all dead. Main fuses good. 73, Mike AC5P __ 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 Message delivered to arch...@mail-archive.com
[Elecraft] KPA 500 failure
Hello list members I just finished putting together a KPA 500 which seems to be having problems. When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation? __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA 500 failure
I also just finished my new KPA500 build. Not 15 minutes ago. I didn't realize that the Fuse block is empty. Good thing i decided to actually double-check it before applying mains power. I figured they'd put the fuses in based on the power cable i ordered (US version, 115 V). Also, that whole business of selecting the right TAP (yellow is the default). But after doing these checks the amp turned on ok and is showing 72.9 V when tapping HV button. __ Slava (Sal) B, W2RMS w2...@arrl.net On Jun 8, 2014, at 9:40 AM, Jorge Mejia lauss...@me.com wrote: Hello list members I just finished putting together a KPA 500 which seems to be having problems. When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation? __ 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 Message delivered to sla...@nullserv.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA 500 failure
I'd start by checking ALL wire connections. Be sure you have fuse block connected properly for your input voltage and proper fuses are installed. Call Elecraft first thing tomorrow for assistance. Good luck! Mine showed no high voltage at first. Found a shorted by-pass cap (tiny SMD type) on board near the high voltage socket and removed it. No problems since! Sent from my iPhone ...nr4c. bill On Jun 8, 2014, at 9:40 AM, Jorge Mejia lauss...@me.com wrote: Hello list members I just finished putting together a KPA 500 which seems to be having problems. When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation? __ 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 Message delivered to n...@widomaker.com __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA 500 failure
Jorge; Check the ribbon cable connections going to the front panel. This sounds like one of those cables is not connected properly. The chief candidate is the 40-pin cable on the left side that goes from the Front panel board to the IO board. You should deb able to get the KPA going. If we can’t get you going with it today, then be sure to contact tech support tomorrow. Jack Brindle, W6FB Elecraft Engineering On Jun 8, 2014, at 6:40 AM, Jorge Mejia lauss...@me.com wrote: Hello list members I just finished putting together a KPA 500 which seems to be having problems. When I turn on and try to run the voltage test, the “HV” button does not respond …. the led’s bar graph indicate 100 W and I can’t turn it off from the front panel switch, I have to use the one on the back, neither can I hear the fan discharging the caps. when switched off from the back. Has any of the list members experienced this situation? __ 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 Message delivered to jackbrin...@me.com __ 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 Message delivered to arch...@mail-archive.com
