[Elecraft] Line Audio Output Mod

I'm really confused. I have a KIO3A, Rev A, C 2007. According to the Mod instructions this board should need the resistance modification. BEFORE I began the mod, the resistance across R19 and R20 was about 51 ohms each. So how can I put a 51 ohm resistor in parallel with R19 and 20 and

Re: [Elecraft] Line Audio Output Mod

Sounds like either that mod has already been done or your KIO3 board is newer than you think. IIRC the original value of R19 and R20 was 600 ohms. Adding a 51 ohm resistor in parallel gives 47 ohms. The newer boards have 51 ohm resistors in place of the 600 ohm units. Perhaps Elecraft

Re: [Elecraft] Line Audio Output Mod

Dave, which part of the instructions indicate your board needs the mod? The Elecraft Web site says K3's before: about Oct 7, 2008, about S/N 1900 The revision marked on your board has no bearing on this. Boards needing the mod will measure 604 ohms at R19 and R20 as Joe mentioned. 73, Barry

Re: [Elecraft] Line Audio Output Mod

Barry is correct. The Revision number printed on the board is for the PC Board layout itself, and has little relationship to the version of the populated board. This is not an Elecraft only situation, it is common in the industry. This is quite common with computer option cards as well,