Don - Thanks for the e-mail. I didn't clean the board, so that's OK. After I got your email, and the response of the reflector seemed to say that this isn't a common issue, I started to look at the schematic around U3. What I did notice is that the two switches share a common data line (D4) to U2. There could be an issue with the pull-up voltage on that line which might make if flaky across the Bank 1/Bank 2 transition. So I will take the K2 apart and check U2, U3 and the resistor bank on D4.
Thanks for the suggestions. 73 John N9RE On 7/30/2011 2:44 PM, Don Wilhelm wrote: > John, > > That sounds like there is some sort of path between the BANK1 and BANK2 > signal lines on the front panel board. > Did you attempt to clean the board of solder flux? If so, you may have > left some residue on the board (likely under the switches) that now must > be completely cleaned, even if that means removing the switches. > The combination of flux and solvents can create conductive paths that > are very difficult to track down. Do not remove the flux, it is not > conductive (just looks messy). If you must clean off a really messy > looking area, do it with a bit of alcohol applied sparingly with a Q-tip > or other small swab and work in a small area at a time. Make sure you > get it all off in that area, as I indicated, leftover flux plus solvent > can be conductive. > > If you did not attempt to clean the board, then look very carefully at > the soldering of U3. Reflow the solder adding a bit of solder (actually > you will be adding a bit of flux). > > 73, > Don W3FPR > ______________________________________________________________ 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
