Re: [Elecraft] Elecraft KPA500 sn 1910 dead
I was gifted a KPA-500 in Aug. 2019. Used about a month before It blew a main line fuse. That was replaced and the amp remained dead. What happened was the center bolt holding the power transformer was not torqued down properly and when the amp was tilted the core shifted into the low voltage supply and damaged it requiring replacement at the Elecraft shop. Hopefully, that is not what knocked out your 12 volt supply? 73, Mike AC5POn Monday, January 17, 2022, 12:52:13 PM CST, Jack Brindle via Elecraft wrote: I would not go by this. Many, if not most, KPA500s do not have noticeable hum when powered. Neither of mine do except for once in a while when the line voltage increases for a short time. If yours does have noticeable him, you may want to check the tightness of mounting nut for the power transformer and retighten if needed (assuming it bothers you). There is a spec for the tightness of that nut. I believe it can be found in the assembly manual, if not also in the operating manual. 73, Jack, W6FB > On Jan 17, 2022, at 3:08 AM, Dave wrote: > > When the rear power switch is turned on, you should hear a hum from the > transformer. The noise level from my KPA500 is quite audible from 2 or 3 > feet away with everthing else turned off. If you don't hear the hum, it's > likely there isn't power reaching the transformer. > > 73 Dave G4AON > __ > 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 a...@sbcglobal.net __ 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] Elecraft KPA500 sn 1910 dead, update.
Call tech support? On 1/17/2022 12:57 PM, Sam Sargent via Elecraft wrote: Elecraft KPA500 sn 1910 dead. UPDATE 12/17/21 First. Thanks to everyone who has responded to mypost. I have read all comments withinterest and have responded to several folks who offered ideas that I havetried. Thank you for trying to help. SECOND. Here is a bit of extra info that I havediscovered. I disassembled the fuse blockand cleaned all contacts and the fuses with the “Deoxit” product. I configured my “OWON HDS272S”meter/oscilloscope to measure resistance and noted that the leads are about 0.7ohms. I connected the meter leads to theflat prongs of the 115vac cord that was plugged into the fuse block on theKPA500. With the rocker switch on thefuse block 3 in the OFF position (o) the meter showed zero (0) ohms. With switch 3 ON (!) the meter showed 2.8ohms. Thus, subtracting the resistance inthe meter leads, the resistance through the fuse block changed from 0 ohms to2.1 ohms. I connected the 115vac cord tothe wall socket and went through the power up procedure. No joy. I listened for the hum of the transformer, and there was no hum. I am flummoxed! CONCLUSION. Thisleads me to believe that the power cord, fuses, and fuse block are functioning. I think that my next step is to look into the possibilityof sending the KPA500 to a repair facility. I am open to your ideas. 73 Sam __ 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 w...@w0mu.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] Elecraft KPA500 sn 1910 dead, update.
Did you get this email? The parked green and red wires and the connected yellow wire should have voltage with only the rocker switch on the back engaged. These are connected to the secondary of T1. If you don't have any voltage, I'd suspect the fuse/switch module. You can unplug the module and check where the wht, yel, ble and blk wires connect. Check with Elecraft and see what pin in 115vac and what pin is neutral. The module is a pm0sxdbx0 power entry module, and you can look for a spec sheet on the web. I think Mouser has them in stock or you can get one from Elecraft. There are two additional fused lines that run to transformer T3. This transformer supplies voltage for the 12 and 5 volt regulators and the interlock switch. On 1/17/2022 2:57 PM, Sam Sargent via Elecraft wrote: Elecraft KPA500 sn 1910 dead. UPDATE 12/17/21 First. Thanks to everyone who has responded to mypost. I have read all comments withinterest and have responded to several folks who offered ideas that I havetried. Thank you for trying to help. SECOND. Here is a bit of extra info that I havediscovered. I disassembled the fuse blockand cleaned all contacts and the fuses with the “Deoxit” product. I configured my “OWON HDS272S”meter/oscilloscope to measure resistance and noted that the leads are about 0.7ohms. I connected the meter leads to theflat prongs of the 115vac cord that was plugged into the fuse block on theKPA500. With the rocker switch on thefuse block 3 in the OFF position (o) the meter showed zero (0) ohms. With switch 3 ON (!) the meter showed 2.8ohms. Thus, subtracting the resistance inthe meter leads, the resistance through the fuse block changed from 0 ohms to2.1 ohms. I connected the 115vac cord tothe wall socket and went through the power up procedure. No joy. I listened for the hum of the transformer, and there was no hum. I am flummoxed! CONCLUSION. Thisleads me to believe that the power cord, fuses, and fuse block are functioning. I think that my next step is to look into the possibilityof sending the KPA500 to a repair facility. I am open to your ideas. 73 Sam __ 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 aj8mh-ra...@charter.net -- Joe Hutchens AJ8MH - Radio Marquette, MI __ 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] Elecraft KPA500 sn 1910 dead, update.
A bit of a long shot - I presume you’ve checked the cover interlock switch? 73, Alan - G4GNX > On 17 Jan 2022, at 19:57, Sam Sargent via Elecraft > wrote: > > > Elecraft KPA500 sn 1910 dead. > > UPDATE 12/17/21 > > First. Thanks to everyone who has responded to mypost. I have read all > comments withinterest and have responded to several folks who offered ideas > that I havetried. Thank you for trying to help. > > SECOND. Here is a bit of extra info that I havediscovered. I disassembled > the fuse blockand cleaned all contacts and the fuses with the “Deoxit” > product. I configured my “OWON HDS272S”meter/oscilloscope to measure > resistance and noted that the leads are about 0.7ohms. I connected the meter > leads to theflat prongs of the 115vac cord that was plugged into the fuse > block on theKPA500. With the rocker switch on thefuse block 3 in the OFF > position (o) the meter showed zero (0) ohms. With switch 3 ON (!) the meter > showed 2.8ohms. Thus, subtracting the resistance inthe meter leads, the > resistance through the fuse block changed from 0 ohms to2.1 ohms. I > connected the 115vac cord tothe wall socket and went through the power up > procedure. No joy. I listened for the hum of the transformer, and there was > no hum. I am flummoxed! > > CONCLUSION. Thisleads me to believe that the power cord, fuses, and fuse > block are functioning. > > I think that my next step is to look into the possibilityof sending the > KPA500 to a repair facility. I am open to your ideas. 73 Sam > __ 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] Elecraft KPA500 sn 1910 dead, update.
Not sure if this has been suggested: did you check the fuses on the power supply board? Those will kill the LV supplies and will keep things from powering up. Ken K6MR From: elecraft-boun...@mailman.qth.net on behalf of Sam Sargent via Elecraft Sent: Monday, January 17, 2022 11:57 AM To: elecraft@mailman.qth.net Subject: [Elecraft] Elecraft KPA500 sn 1910 dead, update. Elecraft KPA500 sn 1910 dead. UPDATE 12/17/21 First. Thanks to everyone who has responded to mypost. I have read all comments withinterest and have responded to several folks who offered ideas that I havetried. Thank you for trying to help. SECOND. Here is a bit of extra info that I havediscovered. I disassembled the fuse blockand cleaned all contacts and the fuses with the “Deoxit” product. I configured my “OWON HDS272S”meter/oscilloscope to measure resistance and noted that the leads are about 0.7ohms. I connected the meter leads to theflat prongs of the 115vac cord that was plugged into the fuse block on theKPA500. With the rocker switch on thefuse block 3 in the OFF position (o) the meter showed zero (0) ohms. With switch 3 ON (!) the meter showed 2.8ohms. Thus, subtracting the resistance inthe meter leads, the resistance through the fuse block changed from 0 ohms to2.1 ohms. I connected the 115vac cord tothe wall socket and went through the power up procedure. No joy. I listened for the hum of the transformer, and there was no hum. I am flummoxed! CONCLUSION. Thisleads me to believe that the power cord, fuses, and fuse block are functioning. I think that my next step is to look into the possibilityof sending the KPA500 to a repair facility. I am open to your ideas. 73 Sam __ 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 k...@outlook.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] Elecraft KPA500 sn 1910 dead
I would not go by this. Many, if not most, KPA500s do not have noticeable hum when powered. Neither of mine do except for once in a while when the line voltage increases for a short time. If yours does have noticeable him, you may want to check the tightness of mounting nut for the power transformer and retighten if needed (assuming it bothers you). There is a spec for the tightness of that nut. I believe it can be found in the assembly manual, if not also in the operating manual. 73, Jack, W6FB > On Jan 17, 2022, at 3:08 AM, Dave wrote: > > When the rear power switch is turned on, you should hear a hum from the > transformer. The noise level from my KPA500 is quite audible from 2 or 3 > feet away with everthing else turned off. If you don't hear the hum, it's > likely there isn't power reaching the transformer. > > 73 Dave G4AON > __ > 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
Re: [Elecraft] Elecraft KPA500 sn 1910 dead
When the rear power switch is turned on, you should hear a hum from the transformer. The noise level from my KPA500 is quite audible from 2 or 3 feet away with everthing else turned off. If you don't hear the hum, it's likely there isn't power reaching the transformer. 73 Dave G4AON __ 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] Elecraft KPA500 sn 1910 dead
"I have exhausted all the troubleshooting ideas that are within my capabilities. I hope that another KPA500 owner may be able to provide information that I can use to get my amp up & running. " Do you have the schematics and a voltmeter? One of the first steps may be to ensure the low voltage power supplies are working. Perhaps, even before that, use a "Kill-a-Watt" or similar to see what current the KPA500 is drawing from the 115 V outlet. Mine takes 0.15 A powered in STBY mode. 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
