Hello Fabio
i replaced U310 (with the help of another Tekscopes member) and this solved the problem. The 20ns, 10 ns and 5ns timing is now correct. I made most of the adjustments in the manual to maximise the amplitude of the waveforms and these seem to be in spec. The amplitude of the 2ns appears down slightly, but this is probably to be expected when using a Tek 2465A with only 350MHz bandwidth to measure it. I can't of course check the 1ns output without a wider bandwidth scope.
Thank you once again for your assistance.
Regards
Kerry
