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| Rigol DS1052E CH2 microphony ? |
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| Fraser:
I was doing some tests on my new DS1052E when I discovered that Channel 2 appears to be sensitive to the DSO's case being tapped or bumped. The effect only occurs on the 5mV or 2mV ranges in AC or DC, but not GND, and appears as a very brief burst of noise on the flat trace (no signal being input to DSO). My first thoughts are "dry joint" and in the past I have found some SMD components that only have a pressure contact with the solder pad and a poor or non existant solder joint, so that is a distinct possibilty here. I would like to check that this isn't just a 'feature' of the DS1052E present on other units before I dive inside it's case. Has anyone else got this occurance on their DS1052E please ? If not, the next step will be to grab the screwdriver and do some hunting inside the CH2 input module. |
| sonicj:
might want to swap leads before you go tearing into it. ;) -sj |
| PeterG:
Does this happen when you remove the test leads? If it does, have a look at this video Dave did a while ago showing something very similar to what your seeing. http://www.eevblog.com/2009/06/21/eevblog-14-a-rather-unusual-oscilloscope-phenomenon/ Just my 2cents. Regards |
| Fraser:
Thanks for the suggestions guys. I have seen Dave's interesting video on the proble pulse but this differs in scenario and is a complex noise band across the screen. My quick and dirty test was carried out with the DSO running with open inputs, i.e. no test leads attached and with BNC inputs unterminated. I considered static discharge and loose input connectors etc but the odd thing is that it is only found on CH2 and at a very low level. I could just ignore it but I have a niggling suspicion that there is a dry joint in there scratching away when the DSO's case is bumped. I will do further tests with a decent input signal and see how it behaves. The idea of hunting an intermittant contact inside a DSO stuffed with SMD parts does not fill me with glee :-[ If/when, I discover what is going on, I will report here. |
| sonicj:
its actually not all that scary inside. the inputs have a shield over them though and im not sure how much effort is involved with removing it. the other thing is that you'll be breaking the warranty seal (if it still applies). -sj |
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