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My MFJ-259B has decided that a 100pF capacitor is a 600 ohm resistive
load at 2MHz, and really seems to be having problems with capacitative reactances. Inductive reactances and pure resistances are a little better, but something is distinctly wrong. Pure capacitances are showing up with large resistive components across much of the frequency range of the unit. W8JI's calibration site suggests detector diode failure as a common cause for sudden problems, but I wonder if anyone else has had this happen? Is it likely the diodes? Also, if I do need to replace diodes, where can I get some HSMS 2829 Schottky Detector diodes (I think these are the ones?) without having to order 100 of them from Newark? I've looked through Digikey, Allied, Newark, Mouser, Jameco... doesn't look good. This thing is long out of warranty, it seems like MFJ service times are in the month+ range at least, and i've got access to a temp controlled soldering station and I'm not scared to swap surface mount stuff. Then again, if I can't get the diodes or can't get them in less than a month, I should probably just send it back to MFJ and pay their repair fee; they've at least got the diodes. Any comments or suggestions on what I should do? I'd rather not be without it for an extended period. Dan |
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