Mike,
OK, back up a step and look at the amplitude of the passband when using Spectrogram. The OP1 filter and the other filters should have close to the same amplitude when the K2 is fed with a broadband noise generator. Please verify for that condition. 73, Don W3FPR On 6/17/2012 7:04 AM, VK1OO wrote: > 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:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
