Just as I always try to remember to set my Scope coupling to Grd and Vertical amp to min sensitivity ... I do the same with SA ie max Attenuation at 'turn-off'.
Also, I have built my own DC block with BNC connectors, and diodes to take out voltage spikes (circuit suggestions are on web) ... again, not foolproof.
Cheers, Ian

--
Cheers,
Ian,
Melbourne, Australia