Rigol DS1102e issue - Page 1
Forum section: electronics / testgear

author: kilomono
author_rank: Newbie
timestamp: February 02, 2014, 04:08:38 pm
content: I bought a DS1102e about a year ago. This week I used the self-calibration feature and since that time I have had a terrible problem!Whenever I turn the oscilloscope on I see a periodic signal on the scope with a frequency of about 100 MHz. A signal appears on both analog inputs and it changes shape, but not frequency, when channel 1 or channel 2 is switched on/off. When the timescale is greater than or equal to 500 ns/div this problem manifests itself as a DC offset. The signal persists even when nothing, other than the power cord, is connected to the scope. I have retried the self-calibration and also reset the scope to the factory default settings and the problem persists. More interesting still, the waveform scales with the vertical scale; i.e. its pk-pk amplitude always appears to be about 6x the vertical scale (e.g. 1 V/div scale: 6V pk-pk amp, 10 V/div scale: 60V pk-pk amp). I have attached shots of the waveformsI've Google searched this issue (which turned up this forum) and I've also searched this forum and been unable, in all my searching, to find a solution. I've also contacted Rigol Tech support, but haven't heard back from them yet. I'm running firmware v. 3.01Has anybody else seen this issue? Does anyone know how to fix it?Thanks!ATTACHMENTS:Figure1: Signal on channel 1; nothing connected to inputFigure2: Signal on channel 2; nothing connected to inputFigure3: Signal on channel 1 when both channels are on; nothing connected to inputsFigure4: Signal becomes a DC offset at timescales greater than or equal to 500 ns/divFigure5: Signal scales with the vertical scale. Note: Fig. 1 is 1 V/div, Fig. 3 is 10 V/div, Fig. 5 is 2 V/div

author: kilomono
author_rank: Newbie
timestamp: February 03, 2014, 08:09:30 pm
content: Rigol's technical support said they had never encountered my problem and asked me to ship my scope to their nearest office. I didn't want to do that, however, so I tried some more things to fix the scope on my own. I ended up connecting a probe to channel 1 and shorting the probe to its ground clip. For some reason this idea kept pressing on my subconscious and I had to fulfill it. I ran the self-calibration with the shorted probe connected to the scope and after the self-calibration finished the problem was gone. Now I can't reproduce the problem and the scope seems to work normally. I have even tried the self-calibration feature without the probe connected (like I originally did when the issue first arose) and have had no success in reproducing the problem. I wouldn't say what I did was the solution to the problem; however, the problem is gone for now.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 03, 2014, 10:02:26 pm
content: Cool! Thanks for sharing your experience.

author: mcinque
author_rank: Unknown
timestamp: February 03, 2014, 10:10:38 pm
content: Thanks for sharing, this could be useful. Just for reference: wich firmware version do you have installed?

author: kilomono
author_rank: Newbie
timestamp: February 04, 2014, 07:22:45 pm
content: You'll see in the first post I specified that I am running firmware 3.01

author: kilomono
author_rank: Newbie
timestamp: February 12, 2014, 03:43:28 pm
content: One more note on this issue. I very seldomly use the autoscale feature on my oscilloscope, however the phantom signal problem has very intermittently repeated itself since I "fixed it" on February 4. When I have noticed it happening again I've just pressed the autoscale button and the issue disappeared back into the recesses of the scope and out of my view.It seems there has to be some internal signal in the oscilloscope that is bleeding over into the measurement circuitry. I have noticed that there is some correlation between the clicks the oscilloscope makes when it is changing scales (presumably relays switching states) and the persistence of the problem, but I have not yet been able to pin down and achieve repeatability of that correlation. If I ever get a second oscilloscope I may dare to dismantle this one and see what I can find out; however this scope is presently my workhorse and any downtime is a great inconvenience. I'm tempted to do a firmware update, but when I contacted tech support I was notified that a firmware update voids the warranty on the scope unless it was advised by tech support to fix a known bug. So if I update the firmware and the problem gets worse I can't be sure they'll cover it under warranty.

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 12, 2014, 11:51:54 pm
content: Quote from: kilomono on February 12, 2014, 03:43:28 pmThat's bullshit, plain and simple. Who the hell told you that nonsense?

author: kilomono
author_rank: Newbie
timestamp: February 13, 2014, 03:44:53 pm
content: Quote from: Mark_O on February 12, 2014, 11:51:54 pmMaybe I worded that too strongly in my post. I don't think I ever read that it voids the warranty, but it seemed like they could use it as an excuse to say my problem isn't covered under the warranty. Nobody ever said that verbatim, I just pieced it together from the document they sent me with the new firmware. What do you think?QuoteQuoteQuoteQuote

author: Mark_O
author_rank: Frequent Contributor
timestamp: February 13, 2014, 11:40:17 pm
content: Quote from: kilomono on February 13, 2014, 03:44:53 pm

author: TMM
author_rank: Frequent Contributor
timestamp: February 14, 2014, 03:31:05 am
content: I would imagine the disclaimer is more to protect themselves against people who have goofed up the firmware flashing progress, rather than the upgraded firmware causing a problem after it was flashed successfully. Rigol don't want to have to be re-flashing everyones scopes for free when the firmware upgrade fails.