Hi Don,
many thanks.
I emailed to MFJ in parallel and I got short reply "schottky diodes surface mount 2820s"...
Which is surprising me a bit as I expected some damage around the power supply circuitry but these diodes are in RF detector part.
In worse case something like $75 + s/h would not be big issue for me just as I am in central EU so i am worrying if the cost will not be a bit high.
He could smell the stench when he reversed the polarity of the ext. power to his MFJ-259B.
So if the SMD Schottky 2820s could use this problem it would be nice.
I asked MFJ support kindly for some schematics or details to locate them and confirm it?
In all cases many thanks Don !
73 - Petr, OK1RP