ROHDE & SCHWARZ SMDU and SMDU Z1 test set owners!

[py1dkw@yahoo.com]

I had worked with this nice test set from 1984 to 1999 and now I could get the same unit here in Brazil. The R & S Support gave the available manuals, but my SMDU is changing its frequency in RF generator mode fast, but only in the lower band, the upper bands are ok and not out of lock. Does any owner of SMDU knows where I could start looking for the defective part? I had the SMDU Z1 unit restored and works fine. Many thanks, 73s Sam Rocha, PY1 DKW