On Tue, Oct 30, 2018 at 01:11 PM, Chuck Harris wrote:
Hi Chuck, this certainly makes a lot of sense. Thanks for clarifying it, never heard this simple and logical explanation from anyone else, other that people being very happy when they see low numbers on those counters on a newly acquired scope. This one does not have any past cal stickers at all, so wonder if it ever was calibrated after being purchased.
Since I am new to this model, I noticed that when pressing any front panel switch, all the other indicators seem to very briefly flash in unison before the requested change is executed. Is this normal? Also, under certain conditions, specially when using the x10 horizontal magnifier and on the lower vertical v/div ranges (10mV and bellow), the traces seem somewhat blurry. But without changing the v/div range they clear up nicely and look very sharp when I engage the 20MHz BW limit, tough. Would this possibly mean HF power supply noise or power line ripple creeping into the circuits? (aging filter caps that need to be replaced?). I have not yet gotten to checking all the power rails at J119, will do so when the Mouser parts order arrives and the cover needs to come off again.
The other issue I've seen is that the automatic frequency measurement (press the measure button and then select 1 for frequency) is off usually by at least 10% or so, sometimes even more. Accuracy of the internal 10MHz reference oscillator not really being that accurate? If so wish there was a way to retrofit an external 10MHz ref input, which I understand is one of the standard options. I read somewhere that it is fairly easy to do it, but found no detailed information. As a comparison, my 2247A will always read the frequency very accurately, and its off by just 71Hz tested against a freshly calibrated rubidium oscillator.
Lastly, I figure you're probably the best person to ask this. On the installed options sticker on the back, the only field marked (punched out) is 46 (between the 22 and 1E fields) on this rear aluminum sticker. So far I have not been able to find any reference at all for an Option 46 on these scopes, and nobody that I asked so far seems to know. Are you by any chance familiarized with what this option 46 entails?