This is helpful. I often use Line sync on olde tyme oscilloscopes, something that is missing from the Picoscopes due, I expect, to the total lack of Mains AC in the scope to synch from. A cheap and easy solution would be to feed mains into the EXT input. With proper conditioning, of course. If the EXT has some protection built into it, then maybe all a fellow would need to do is use a stepdown transformer to isolate and reduce the mains voltage, and use a large enough series resistor between the transformer secondary and the EXT input do bring transients and nasties into manageable range.
Does Picotech have any off-the-cuff guidelines for something like this?
-- mike elliott