What's your measurement setup, and what capacitance (and resistance)
values are you seeing?

If you're seeing significantly higher capacitances, then I wonder about
fixturing. Or maybe whoever did the repair wasn't careful about parasitics.

If you're seeing just somewhat higher C and lower R, then perhaps you
could try some 1N5711s. These are often double-marked as 5711/6263, but
the original 6263 had 10-15% or so higher capacitance, IIRC.

That is a fine instrument, for sure, and I hope you will get it back to
like-new performance. It's also fun to use as a front-end for a 1GHz ETS
sampling scope.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070


On 5/6/2024 9:41 AM, jmr via groups.io wrote:
> The main problem is that the input capacitance of the probe is too
> high and the Rp is lower than it should be up at VHF when compared to
> a good probe. I think this could be caused by the wrong choice of
> diodes (1N6263). I won't know for sure until I'm able to take the
> diodes out of the probes. It's not my VVM yet so I can't do any
> further internal testing.