Don, Still no joy with this problem. I've resoldered most of the joints on the KSB2, checked the torroids etc and have gone back and checked the filters with a noise generator and spectrogram. What feature of the circuit would account for the increase in S meter bars?
Mike VK1OO On 10-Jun-12 10:12 AM, Don Wilhelm wrote: > Mike, > > Two different filters - the FL1 OP1 filter is the one on the KSB2 > board while the others are created from the variable bandwidth filter > on the RF board. Since all but OP1 work correctly, it has to be the > OP1 filter on the KSB2 board. > > Oh, one more piece of info - when you remove the KSB2 board, the OP1 > filter goes away, and the filtering defaults to a 2.20 bandwidth > filter from the filter on the RF Board. > > 73, > Don W3FPR > > On 6/9/2012 7:54 PM, VK1OO wrote: >> Hi Don, >> >> Wow, thanks for fast response noting it must be late there. >> >> I will do. What conclusion can be drawn from X1 being affected, and >> not X2-4? >> >> Mike >> VK1OO >> >> On 10-Jun-12 9:43 AM, Don Wilhelm wrote: >>> Mike, >>> >>> It is on the KSB2 board somewhere. Check everything on the end of >>> that board containing the filter crystals. Check T1 and T2 to be >>> certain all the leads are well stripped, tinned and soldered and be >>> sure there are no shorted turns on those toroids. I recently >>> repaired a K2 that had the shorted turn problem because the builder >>> use a flame to burn off the insulation from the toroid wires and got >>> too much flame on the red T2 wires when he tried to strip the green >>> leads. >>> >>> 73, >>> Don W3FPR >>> >>> On 6/9/2012 7:29 PM, VK1OO wrote: >>>> Hi Don, >>>> >>>> We have a long weekend here, so I've been able to get back to this. >>>> I reflowed RF board and KSB2 board, with no improvement. >>>> >>>> I then took out the KSB2, inserting the previously removed links >>>> and the capacitor (effectively returning radio to pre-KSB2 state). >>>> The noise problem on X1 goes away. >>>> >>>> Your thoughts on what to look at next would be appreciated. >>>> >>>> Mike >>>> VK1OO >>>> >>>> >>>> On 03-Jun-12 6:59 AM, Don Wilhelm wrote: >>>>> Mike, >>>>> >>>>> If you do not find the solution re-flowing the solder on the RF >>>>> board filter area, the problem source may be on the KSB2 board in >>>>> the switching diodes and/or resistors at the filter end of that >>>>> board, so for completeness, reflow those connections as well. >>>>> >>>>> 73, >>>>> Don W3FPR >>>>> >>>>> On 6/2/2012 4:24 PM, VK1OO wrote: >>>>>> Don, >>>>>> >>>>>> The effect happens when the antenna is disconnected as well as when >>>>>> connected. >>>>>> And in SBB and CW >>>>>> >>>>>> SSB Filter Widths >>>>>> X1 = OP1 >>>>>> X2 = 2.4 >>>>>> X3 = 2.1 >>>>>> X4 = 1.8 >>>>>> >>>>>> CW Filter Widths >>>>>> X1 = OP1 >>>>>> X2 = 0.7 >>>>>> X3 = 0.4 >>>>>> X4 = 0.1 >>>>>> >>>>>> I assume something is going wrong in the 4.915MHz Variable Bandwidth >>>>>> Crystal Filter. >>>>>> >>>>>> >>>>> >>>> >>> >> > ______________________________________________________________ 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
