Brian, Why speculate, just remove C31 (it needs to be replaced anyway) and remeasure to confirm that C31 is indeed the problem - it quite likely is.
73, Don W3FPR On 1/22/2011 3:11 PM, OZ2BRN Brian Lodahl wrote: > Hi there, > > After 100 % flawless work with the whole K2 journey, the KPA100 and all > the add-on modules with bell's and whistles, it seems my turn has come > now to have a build error on # 6936, or more specificly; the KPA-100: > > When doing the 2nd alignment step of KPA100, I measure all the > resistances OK but one; The cathode of D13 seems very low resistance to > ground and not>10 kohms as expected. I measured some 6-7 ohms. > > The intial checkout in 1st alignment step round confirmed all diodes > pass and having the expected forward and reverse voltages / resistances > as expected, so I assume for now the Diodes are OK still. > > Now I may have myself an idea to the failure mode, but can any of you > think of other (known) failure modes to this ? > > My assumption is that I have shorted out the two foil layers of > capacitor C31; effectively putting both sides of C31 to ground - as I > managed to nick the house of C31 with my auxillary 30W solder iron, when > soldering the emitters of Q1 and Q2, and the plastic housing of C31 is > now slightly open and the internal foil visible. > > ( and yes; I'm givin' myself a hard time and cursing my own lack of > being careful :-) !! ) > > Any other bright ideas beyond the obvious C31 defect, hence replace ? > > 73' > Brian OZ2BRN > ______________________________________________________________ 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
