[time-nuts] 53230A input channel fault?

[Anders Wallin]

Hi all,

I have a 53230A that behaves differently on ch1 and ch2.

With ch2 at DC/1Mohm/postive-slope/1V it triggers ok on my PPS signal and
shows e.g. a pusle-width measurement etc.
The same signal connected to ch1 fails to trigger.

I noticed the Vpp and Vmax/Vmin voltage readings are not correct for PPS
signals - i.e. on a scope my signals are from 0V to 4V, but the counter
shows -5 mV to +5 mV or similar. But perhaps that is because of the low
duty-cycle of a PPS signal.

We were measuring RF frequencies with the counter a few weeks back - it
says max 1W input... it is possible that this was exceeded (does 50Ohm vs.
1MOhm setting matter for input-protection?).
Any ideas on what breaks first on the input stage? :) (are there schematics
online?)


thanks,
Anders