Brightness of waveform with DS1000Z-E Rigol scope

[PatrickB]

Hello,
There is a problem with the display of my DS1102Z-E purchased 2 months ago. 
The waveform brightness decreases a lot when the horizontal time base is equal 5ns and only with this value.
With greater or lower values of time base the brightness is normal.
Take a look on pictures done with different time base ( 2, 5, 10 and 20ns). The display adjusted intensity is about 30%, the readability is good when time base not equal 5ns." alt="" class="bbc_img" />
With the default value of brightness the difference of brightness is lower but there is always a difference with 5ns time base.
The software version installed on my scope is 00.06.03.02.02 and board version0.0.1
What versions of software and card are installed on your scope and do you have this problem?
Regards
Patrick

[PatrickB]

Hello,
I am the only owner of a RIGOL DS1000Z-E oscilloscope and the only one to have this trace brightness problem when the time base is 5ns! ?
I do not believe that.
The owners of this Rigol give me your comments on this problem and the software and card version of your scope.

[manupthehills]

I can totally replicate this issue. It's very visible at default display brightness; a little less at higher brightness.
Lower brightness usually is associated to lower wfms/s, so I was expecting some triggering issues considering the clean signal feed to the oscilloscope (pure sinewave 2.5Vpp)
Connecting the Trigger out to another scope is possible to see that the refresh rate is always ~6k wfms/s regardless the time base.
I believe is a firmware bug.
And on a side I'm wondering where are the 30k wfms/s in the spec sheet... (the other scope delivered 1M wfms/s as promised in the same situation)

[PatrickB]

With what you said, manupthehills in your last post, I made measurements with the following configuration.
An HF generator connected to a single channel of the DS1102Z-E with its trigger output connected to a second oscilloscope.
I measured a refresh of the DS1102Z-E of 30000wfms/s (period of 33µs) obtained ONLY when:
  - only 1 oscilloscope channel is used
  - frequency of the signal generator lower than 10Mhz (approximately)
  - oscilloscope time base is equal to 50ns
These conditions for having the highest refresh rate are certainly different from one oscilloscope to another and from one manufacturer to another and especially the purchase price.

Regarding the brightness problem, I measured under the same conditions as my first post:

DS1102Z-E time Base	Trigger (Time between 2 wfms)
2ns	125µs
5ns	120µs
10ns	57µs
20ns	76µs
50ns	87µs
100ns	150µs
200ns	290µs

The low luminosity of waveform on the screen of the oscilloscope with a time base of 5ns cannot be explained with the refresh rate (wfms/s) of 120µs. This value is higher with other time base values and the luminosity is normal.

As you said, manupthehills, it may be due to a bug in the software or, in my opinion, a hardware problem with the motherboard...

You, the other users of a DS1000Z-E, what is the version of the motherboard?

[Fungus]

As you said, manupthehills, it may be due to a bug in the software or, in my opinion, a hardware problem with the motherboard...

You, the other users of a DS1000Z-E, what is the version of the motherboard?

Han, the image is all software. It has to be a firmware bug.

(also the fact that other people can reproduce it)

[trmntr]

PatrickB,  Hello.  Has the 5ns display brightness issue been resolved?

[PatrickB]

No The problem is not solved.
2 weeks ago I sent an email to Rigol, last week another email and still no response.
Rigol does not respond to emails. There are 2 possibilities for which Rigol does not answer:
1) they do not want to answer because we are not important customers.
2) Rigol knows the problem perfectly well and they have no solution.
Whatever the reason, it's completely unacceptable from a manufacturer like Rigol.
A device may have a malfunction but the manufacturer must take responsibility.
Regards

[trmntr]

Perhaps the problem is not being solved due to the fact that there are too few complaints from customers.  When I get my scope, and if I see this problem in myself, I will write to them too ...

[PatrickB]

You must be right there are not enough customer complaints. When no one complains, manufacturers do nothing to fix the problem.
When you receive your scope tell me the firmware version and the board version. I know there are several card versions but I don't know which ones do not have this problem. Thank you