General > General Technical Chat
The Rigol DS1052E
Simon:
Well like many I seized the moment when seeing a 50 MHz scope going for just £ 239 on ebay, I was unaware of the samples per second rate and its importance at the time but it seems that I got very good value for money for a very nice peice of kit..... well so I thought
It seems that there is a lot of noise on the trace, I have always assumed this to be because the power supply is not screened (naturally I tossed the warranty out of the window and opened it), however on screening the SMPS with tin foil stuck to cardboard not much changed, I've had a slight improvement after also taping a peice of tin foil on top of the input screening box so that it covers the analog support circuitry behind it (refer to daves video number 37 I think) but the interferance remains.
Its rather unusual because as I increase the V/div the Vpp of the interfearance also increases effectivly remaining about the same size on the screen as all V/div settings, now that I have added screening its improved slighty and at 100 mV/div and above its less than at 20 and 50 mV/div (X10 input setting) so bearable.
Has anyone else had this ? or have comments ? I can provide photos of my screening later
kc1980:
Bump. I hope someone answers this. I have an itchy finger on a hair trigger for this Ebay purchase...if ya know what I mean. (pls take my credit cards away from me)
johnnyk126:
In the coments below episode #37 Dave posted few pictures of noise on Rigol and Tektronix. He says that this noise is typical for this class of scope.
http://www.eevblog.com/2009/10/12/eevblog-37-rigol-ds1052e-oscilloscope-teardown/
It is good to know that some DIY shielding can improve performance. Can you post some pictures?
Simon:
right I'm reasured now, yes my interferance is the same as the pics dave put up (Thanks Dave), I'll take some pictures of my shielding and post them later,
I think your best bet is to put the sheet of foil taped to the input screen box over the circuitry behind it first and see if it makes a difference, amazinly screening the SMPS made no difference but I want to check that the foil is connected to the chasis
Simon:
Right pics time:
http://www.simonsphotography.org.uk/ebay/scope1.JPG
http://www.simonsphotography.org.uk/ebay/scope2.JPG
The most important part is the bit of foil stuck to the top of the input screened box, the bit of foil clad cardboard made little to no difference at all, the screws holding the SMPS down will need to be changed for longer ones (i used the ones holding the back on at the top) as the cardboard adds thikness, make sure the foil is connected to the chasis this should happen when screwed down to the mounting pillars but to make sure I nicked the nut and bolt holding the ac input socket to the case and taped a peice of wire to the foild and bolted the other end to the top of the case, again little to no effect. I think the foil around the power sire had little effect to.
what opinion would you guys have on removing the psu completely from the scope and making it external ? only problem is there is a second power wire going into the back of the screen and there are so many power wires, and no they are not all in parralel only some, its like somwe of the power supply is on the scope board RIGHT NEXT TO THE ANALOG SUPPORT CIRCUITRY, very clever rigol, you had the chance to make a perfect scope and flunked it !
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