I've been storing up a list of modifications I wanted to install in my K3 (S/N 01195, July 2008) and managed finally to do them today. Due to the number (nine) and varying descriptions, purposes and locations in the rig, I tried to organize my thinking by putting them in a list, trying to see which ones I really need or want, how hard they might be to install, and which ones might be best done together due to being on the same board, etc. Some are documented in Elecraft's modification kits & parts area and some in the application notes area.
I started by putting all of the PDFs into a directory of "official K3 modifications" so I could study them. The ones applicable to my K3's vintage were - K3AFMDKT --- Improve speaker & line out distortion and IMD K3DSPLPF --- Active audio LPF to reduce artifacts in the audio chain, add daughter board to DSP board K3IOBUFFKT -- Increase signal level at I.F. output by more than 10 dB AFOPMDKT -- Protect audio amp from short circuit or low impedance loads App Note -- Extreme signal RX protection mod App Note -- Protect against RF pickup at microphone connection by bypassing RF choke App Note -- Protect against chirp from synthesizer by increasing DDS signal driving the PLL App Note -- Improve immunity of RS232 and audio connections to RF by bypassing RF chokes App Note -- K3 SYN ALC mod. Assure enough drive when in high temperature environment Descriptions are my paraphrase and might not be totally accurate. Anyway, I did all of these today and made notes on the degree of difficulty and which ones might best work at the same time here - http://pages.suddenlink.net/wa5bdu/k3_mods.pdf If you have a similar vintage K3 and haven't kept up on mods, they might be of interest. None of them were really difficult for me, and the instructions were complete and accurate. I should say, I assembled my K3 from a kit, I do a lot of homebrewing but it's pretty ugly, and my vision wouldn't allow SMT work with just my bifocals, but with a 10x jeweler's loupe jammed into my good eye I do OK. I did all the mods today and didn't put anything back together until I'd finished them all. Doing it this way, it's important to bag or otherwise segregate all of the screws or other hardware from each cover or component removed and keep each piece in a separate place with its own hardware. I was most interested in the lowpass filter. I'm no golden ear, but possibly the power of suggestion made me think I heard some of the harshness others described. I found myself cranking the bandpass way down toward the low end. At least preliminarily, I think I do notice the improvement in the quality of the sound (I work CW) with the LPF installed. I'm pleased with Elecraft's way of publishing instructions and making mod kits available. Not to diss any other manufacturers, but most have a "no user serviceable parts inside" approach. 73- Nick, WA5BDU ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
