Hi Jeff,
My guess is that the in-between attenuations are indeed done fully electronically. It is hard to maintain bandwidth if you vary gain by large factors all-electronically, but factors of a couple are eminently doable. But I haven't looked at the schematics yet, so I can't confirm that's what's done here. But from the info you've given, it's very likely.
--Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
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On 3/22/2022 00:04, Jeff Dutky wrote:
Tom, Ozan,
thanks for the suggestions, I will try making some measurements with the cover off. Is it safe to operate this scope with the cover off, or do I need to provide extra cooling on the hybrids?
Tom, I DO have the schematics, and I think I see the cap and resistor that you are talking about: just after the attenuators there are C100, marked ".001" on the schematic, and R100, marked "470K". I would be very happy to discover that this is just a bad capacitor.
I"m a little confused by the construction of the attenuator, however: there are only three stages to the attenuator, the first switches between 1 M¦¸ and 50 ¦¸ input, and the other two are both marked "¡Â10", but I'm clearly able to select attenuation that is not a simple multiple of ten. How can this attenuator give me all the 1-2-5 ranges? Is there switchable attenuation happening inside the pre amp hybrid?
-- Jeff Dutky
