Problem with Rigol 1052E

[utn56]

Hi

I bought a Rigol 1052E some time ago. It worked so nicely until a week ago I tried to use channel 2. Suprisingly I cannot see signal line anywhere.
The problem is best described in this video:


If I´m doing something wrong, please let me know. I won´t open it, but perhaps it is not a hardware problem, and I can do something before taking it to repair.

By the way, it was never re-firmwared (i don´t trust myself doing such procedures). I only tried self calibration with no results.

Thanks in advance.

[RRobot]

I don't own this scope so I don't know if this is possible. But on my Agilent I can adjust the trace intensity. Any chance you've turned this down by accident for channel two? Does that scope have a factory reset?


Also when you set it to ground coupling it appeared to have a trace, is this true, or was that just a glitch?

[tom66]

To me it looks like the channel is clipping to 255, i.e. max scale. If you zoom out on this scope by changing scale, it simulates the zoom out before getting the new data, hence the reason you briefly see the line.

It's bust, send it back.

If you want to debug it, my first guess would be the Ch2 attenuator or input amplifier, then possibly the ADC switching matrix (two relays), or possibly even at slow sweep speeds, one of the ADCs being faulty. Try seeing if you can trigger off the dead Ch2 (use square wave from calibrator, set trig to AC coupled, 0V amplitude, and enable counter in Utility menu), if you can then it's not the input frontend, but the ADCs or the drivers/mux for them.

[saturation]

Before doing anything further did you reset it to back to "factory", which puts everything at default, not just calibration?  Using the same encoder no problems with channel a?  Report back then, please.

[utn56]

First I want to thank you all for answering, and giving your suggestions.

To me it looks like the channel is clipping to 255, i.e. max scale. If you zoom out on this scope by changing scale, it simulates the zoom out before getting the new data, hence the reason you briefly see the line.

It's bust, send it back.

If you want to debug it, my first guess would be the Ch2 attenuator or input amplifier, then possibly the ADC switching matrix (two relays), or possibly even at slow sweep speeds, one of the ADCs being faulty. Try seeing if you can trigger off the dead Ch2 (use square wave from calibrator, set trig to AC coupled, 0V amplitude, and enable counter in Utility menu), if you can then it's not the input frontend, but the ADCs or the drivers/mux for them.

I tried this and there´s no counting frequency for channel 2.

Then I used the math function, doing CH1+CH2 sum. On ch1 was the probe test generator, and ch2 without signal. Here are the results.

5V/div


10V/div


20V/div


As you can see the DC offset varies with V/div attenuation. So I believe you are right, the input is clipping. I don´t care where the problem is, because I lack the knowledge to fix it. I´ll just take it to repair. The only think which annoys me is the proneness to suicide this chinese stuff shows.

Before doing anything further did you reset it to back to "factory", which puts everything at default, not just calibration?  Using the same encoder no problems with channel a?  Report back then, please.

I didn´t factory reset the oscilloscope, but carefully copied the ch1 config, wich works, on ch2. Definitely I think ch2 is not working properly.

Again, thank you very much.

[MikeK]

Does the "Auto" function work?  It looks like you may need to contact tech support.

[IanB]

Does the "Auto" function work?  It looks like you may need to contact tech support.

Indeed, what Mike says is the simplest test. Connect a probe to Ch1, hook it to the probe compensation test point and press "Auto". You should get a nice square wave in the middle of the display. Now, using the same probe, switch to Ch2 and repeat the test.

If either test doesn't work, there is a fault in the scope. If both tests fail, try another probe in case the probe is at fault.

[Psi]

Lift the scope up, turn it upside down and give a shake.

Maybe there is a bit of solder or metal inside which is shorting the channel high.

[KTP]

Lift the scope up, turn it upside down and give a shake.

Now you know why Psi doesn't have kids 

[Psi]

hehe

[saturation]

You're welcome, but think on the bright side, you found the fault early. 

I think its important for owners to burn-in their new purchases, like you did here, to catch defects.  Production of any product, China or not, is not 100% error free, so its prudent to expect faults, and be able to return them ... which is covered by most vendors or manufacturers warranty. 

That's why its risky to buy direct from China for anyone outside of China, for something as heavy and expensive as a DSO, in case it does have a defect.  Returning it would not be easy.

In the past year of eevblog reviews, Dave has had an Agilent DSO die on him during a review, as well as revealing serious firmware bugs in the first releases of  Agilent 1272a DMM.

Since most Rigol 1052e class scopes work as the manual says it should, its a good bet that you have a production defect, not a design or firmware defect, that slipped QC.  Now compare to the woes of firmware issues such as in some Atten or Siglent scopes; these problems would not be fixable without an update; exchanging it for a new same model scope will not improve the fault.

As you can see the DC offset varies with V/div attenuation. So I believe you are right, the input is clipping. I don´t care where the problem is, because I lack the knowledge to fix it. I´ll just take it to repair. The only think which annoys me is the proneness to suicide this chinese stuff shows.

Again, thank you very much.