I have a Kenwood dual trace CRO that appears to be in good working order.
Each channel works fine independently, but when I cannect the probes one each to two points on the same circuit (ref to common ground) something that looks like low level oscillation appears on channel 2.
I tried swapping the probes, both between channels and test points. The result is always the same, and always on ch. 2
There is nothing unusual about the input signal. Just audio 2Vpp. The probes are nearly new.
Is it set to "chop" mode? There is probably a cluster of calibration trimmers for getting that working cleanly. It's best avoided except at slow sweep rates.
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On a sunny day (Fri, 18 Dec 2015 14:21:09 +1100) it happened Robert Stevens wrote in :
I had some oscillation very much like that in my Trio analog scope once, after long time no use (month?) Switching it off and back on a couple of times made it go away though. I wondered if it was perhaps bad contacts, or just electrolytic capacitors that had gone bad, and came back after some time reformatting. But then it is from 1979 so...
Need alot more info. First of all, if you connect them to the exact same po int, does this happen ?
Are you connecting both ground clips, to different points or the same ?
What is the DUT or UUT ? an amplifier ? If so loading a certain point with the probe could upset the feedback network in certain amps that have a high open loop gain.
Usually, when you use two traces on an amp, just use one ground. there is s uch a thing call4ed ground current and you do not want it going through the scope. where to put the ground you do use depends on a few things. How muc h gain are we talking here ? Usually you want the ground on the point with the lower signal level. But then there are exceptions.
Also I assume you know the first rule of scopes right ? ALWAYS use 10X prob es. Only switch to 1 X when you ABSOLUTELY need all that gain. You would be surprised how different things read. Things you would not expect. Not like the grid of a tube or the gate of a MOSFET or whatever. It is not do much the DC loading, it is the HF loading.
One of the laws of physics is that you cannot measure anything without affe cting it. the idea is to affect it as little as possible.
On a sunny day (Fri, 18 Dec 2015 20:19:31 -0800 (PST)) it happened snipped-for-privacy@gmail.com wrote in :
Cool, need expert witnesses like you: :-)
It is even much worse, with Microsoft and software, you do not own it, etc... Take a picture puppy-right Selling used software .. Anyways I did say it, and now say it again: "USA is the country with more lawyers than people."
In any country the state has the authority to make a poor man a rich man, and a rich man a poor man at any time, take away your freedom, or give it to you.
That is the way it is.
Maybe *bulb comes on* one day private flights to habitable other planets will (cost you dearly) happen that have only you on those planets to decide, well but as soon as a couple goes there there will be more, and a fight over who can do what, so it is in the species.
The other case is where civilizations collapse say due to glow ball war or - worming.
I looked at civilizations like at a solidifying crystal. In the beginning there is a lot of motion, energy, a fluid, things move. Then slowly things crystallize in ever more fixed structures, and nothing can move (the law, the rules, the lawyers, the 'system'). Something with entropy and the Universe cooling down perhaps, death the heat of the nuculear bombs may temporarily bring it back to life, melt the structure, but the tendency is the same, stars cool and die. But I just woke up and the philosophy sigh...
Thanks for your insight into that power line, good to know, gotta find a location now... :-) Na, wind power, mm wonder who owns the wind.
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