As Dave mentioned the LED board is in the power supply. Take off the cover of the power supply and the LED board is small board located on front left side as you look at the amp from the rear. It’s held in place by two small screws. The resistor to change is located bottom of the board as your looking at it from the rear of the amp. The resistor needs to stand off the board a couple of mm.
Your question regarding the SN when this change occurred is a good one. I don’t know the answer. My amp was one of the first with a very low SN. 73 > On Jun 27, 2020, at 6:43 PM, Dave <rocke...@gmail.com> wrote: > > It is the LED board in the PS. > > Dave wo2x > > Sent from my iPad > >> On Jun 27, 2020, at 7:55 PM, ex...@comcast.net wrote: >> >> Hi Steve, >> >> Thanks for the update. >> >> So, this is the LED board on the amp, not the power supply? Guess we don't >> know at what serial number the change was made? >> >> Mike >> K7PI >> >> >> -----Original Message----- >> From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On >> Behalf Of STEPHEN R ZUMBRUN >> Sent: Saturday, June 27, 2020 16:39 >> To: elecraft@mailman.qth.net >> Subject: [Elecraft] KPA1500 Power Supply Fan Noise >> >> Hello, all and Happy Field Day. Say I just wanted to comment about Elecraft >> service and the help they provided me to make a mod to my KPA1500. My >> KPA1500 power supply fan was rather noisy. I had seen discussion on the >> reflector about this so I contacted Doug at Elecraft service. He ask if I >> could solder. I informed him I could and he sent me a new 22 ohm, 3 watt >> resistor and i swapped it out with the 10 ohm, 3 watt resistor on the LED >> board of the power supply. I am much pleased with the sound of the power >> supply fan now after the modification. My amp is an early serial number and >> the new amps come with the 22 ohm resistor on the LED board. So...if your >> power supply is a bit noisy you might consider this mod and contact Doug at >> Elecraft Service. The Elecraft part number of the resistor is E500128. 73, >> Steve W0SZ. >> ______________________________________________________________ >> 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 ex...@comcast.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 rocke...@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
