K3 DSP Board Upgrade Info
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I have recently ordered a K3DF DSP Low Pass Filter to add to the DSP board in my K3. After reading through the relevant documentation, it appears my DSP board is "Revision B" and therefore does not have the low frequency audio mods for TX/RX either.
It seems that I could not find anywhere that told me exactly what the changes were to effectively bring my DSP board up to the latest spec. I know I could ship my board to Elecraft for upgrade, however the cost of the shipping to/from Australia is expensive. I have looked through both the early and current schematics and believe I have a compiled complete list of the changes for the "Low Frequency Audio Mods": ----------------------------------------------------------------------- Drawing "K3 DSP IF: CODECS" COMPONENT ORIGINAL VALUE NEW VALUE R17 1K 10K R18 1K 10K R19 1K 10K R20 1K 10K R23 1K 10K R24 1K 10K R25 1K 10K R26 1K 10K C28 0.1uF 1uF Drawing "K3 DSP: DAC Audio" COMPONENT ORIGINAL VALUE NEW VALUE C1 33pF 470pF C11 33pF 470pF C9 10uF/25V 100uF/6.3V C13 10uF/25 100uF/6.3V ----------------------------------------------------------------------- For my records, I have drawn circles around the changed components in the relevant schematics and have these as individual pdf pages. If anyone would like a copy, please contact me via email. it would be even better if someone would offer to host them on their site / webspace? Andy VK4KY |
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Here are the files that Andy has put together. I'm sure they'll prove
useful to some: Elecraft Low Freq. Mods 2010_1 Elecraft Low Freq. Mods 2010_2 Elecraft Low Freq. Mods 2008_1 Elecraft Low Freq. Mods 2008_2 ~Brett (N7MG) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Andy Wood
Oops! I left out C44 and C45. The following chart has been amended.
----------------------------------------------------------------------- Drawing "K3 DSP IF: CODECS" COMPONENT ORIGINAL VALUE NEW VALUE R17 1K 10K R18 1K 10K R19 1K 10K R20 1K 10K R23 1K 10K R24 1K 10K R25 1K 10K R26 1K 10K C28 0.1uF 1uF Drawing "K3 DSP: DAC Audio" COMPONENT ORIGINAL VALUE NEW VALUE C1 33pF 470pF C11 33pF 470pF C9 10uF/25V 100uF/6.3V C13 10uF/25 100uF/6.3V C44 0.1uF 1uF C45 0.1uF 1uF ----------------------------------------------------------------------- Andy VK4KY |
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I have now posted the images to the following. Thanks to "The Smiths" for his input and photo of the DSP board.
http://s840.photobucket.com/albums/zz330/VK4KY/Elecraft%20DSP%20Mods/ Andy VK4KY |
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In reply to this post by Andy Wood
I have now completed all of the modifications to upgrade the DSP board to the latest spec and can say that the improvement is worthwhile. For me, the receive audio, especially on ssb, is a lot less fatiguing.
For those wishing to attempt this yourself, here is some more info: - Resistors and chip capacitors are 0603 size - C9 and C13 (100uf/6.3v) need to be the correct size to fit the pcb pads. Panasonic part number EEEFKJ101UAR are suitable. I also found it easier to remove the headphone socket from the pcb to facilitate removal / replacement of these capacitors. My K3 S/N 3017 already had some of the components changed on the DSP board. The only components left for me to do were C1, C11, C9 and C13. My DSP board (Revision B) had a "1" handwritten after the revision number. My guess is mine was a revision "B1"? Andy VK4KY |
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