David G3UNA, wrote: > A quick look at the circuit diagram shows that buttons are taken > from a > potential divider to CD74HC4051M inputs. These switches (unless I've > misread the diagram) will therefore take the input current of the > multiplexer which is typically <1uA. I don't know the spec for the > Elecraft > switch but a similar one requires a minimum current of 10uA. This > should be > checked more rigorously, but it might indicate a potential problem. David,
The K3's front panel switches do not have a minimum required current. I just verified this again with the manufacturer. They have gold- plated contacts on the PC board and should be extremely reliable. Regarding the switch test function in the menu: A small amount of digit flicker is perfectly normal. The A to D converter has an ambiguity of +/- one count, and the firmware algorithm reading the switch has no hysteresis, therefore +/- count of flicker is also to be expected. In firmware, we read the switch voltage several times, average them, and look for the proper switch code based on "bins" that have a large amount of excess margin. So the operator should not be concerned in the least about a deviation of even several counts in their own switch read voltages. If you're experiencing any type of switch-read error that isn't a hard failure, it is probably something that I can improve in firmware. I'll be happy to work with you on this -- please give me a detailed example. 73, Wayne N6KR ______________________________________________________________ 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
