I am a new subscriber to this forum. I read many of the posts concerning the Siglent SDS1202X-E oscilloscope before ordering one 10 days ago from Amazon Canada (no local dealers in Western Canada). There were a few comments about Siglent fan noise but mostly they were about other models like the 1104. . So I hope those of you that own or sell these scopes can help me out.
The unit that I received is a BB model but it must have been in stock for awhile because the calibration letter was dated last February. It was new because the power on screen showed that I was the first to power it up. The firmware was 5.1.3.17 which is not the latest September 2018 release so I will have to update if I don't return the unit. The scope works okay and seems quite accurate in terms of the frequency counter, voltage measurements and FFT operation. Offsets are pretty good on the 500 uV scale.
The problem is the noise. When I power it up in the morning it has some fan noise which is fairly noticeable and at a higher level than I expected. I have a quiet lab without any other fans running most of the time. What I thought I noticed was that the noise was getting louder after a few minutes and then about 10-15 minutes after start there is a whine which may be coming from the fan or the power supply. In order to verify my observation I made a recording by placing a microphone near the fan exhaust grill on the right hand side. I recorded the ambient noise with the 1202X-E turned off. Then a 15 minute recording was made with the scope powered up and nothing connected. I then analyzed the recording with spectral analysis software and confirmed what I had been observing. The plot below shows the difference from ambient noise after at 2, 9 and 13 minutes. One can clearly see the noise slowly getting worse and several spectral peaks which are the "whine" I was referring to earlier.
As it stands it is not enjoyable to use this instrument. I will either have to build a sound-proof enclosure around it (with quiet fans to provide airflow) or return it to Amazon for exchange or refund. If this is the way this product normally operates there is no point in going through the hassle of return shipping just to get the same issue again.
I hope I can get some feedback on these questions.
1. Is this typical for the 1202X-E or do I have a bad fan?
2. Why does it get worse as the unit warms up? The fan is still pushing the same CFM of air - it is just warmer.
3. Could the spectral peaks be something to do with audio noise from the switching power supply?
4. It shipped without a CD in the Quick Start guide. Anything of value on the CD that can't be downloaded?
Thanks for reading and any comments....