Fixing Rigol DS2000 design/manufacturing flaws

[-The_Mask-]

I just read this on Tom's Hardware site.
According to this, it appears that with diy elecronic load is not possible to make accurate results. Perhaps author of this text is participating on this forum?

He doesn't say that. He only stated that it's not repeatable by another person. Simple because a homemade load tester is one of a kind. Sunmoon or Chroma load testers are quite common. If you get some strange results with those load testers another person with the same load tester can verify you results. With a homemade tester that's not possible. Aris knows because his first load tester was a homemade load tester.

[ITelektro]

He doesn't say that. He only stated that it's not repeatable by another person. Simple because a homemade load tester is one of a kind. Sunmoon or Chroma load testers are quite common.

I do not know what to say at this .....
If you use a 7.5 digit multimeter then the results will be not repeatable by other person because 7.5 digit multimeter is not an ordinary, therefore it should not use?
I gave a practical example.
The question is really simple;
What is the difference in the constant load of 1A to a constant dc load of 1A with any other dc load?
If there is a difference, then Aris is right, else is not.

Aris knows because his first load tester was a homemade load tester.

Okay, that tells us that he was not able to make a dc load. What does not mean that this is not possible, as you implying. Just tell us that he was unable to do it.

[-The_Mask-]

I do not know what to say at this .....
If you use a 7.5 digit multimeter then the results will be not repeatable by other person because 7.5 digit multimeter is not an ordinary, therefore it should not use?
I gave a practical example.
The question is really simple;
What is the difference in the constant load of 1A to a constant dc load of 1A with any other dc load?
If there is a difference, then Aris is right, else is not.

There is a difference between 1A load with one load tester and 1A with another load tester, even if they're both exactly 1A.

Okay, that tells us that he was not able to make a dc load. What does not mean that this is not possible, as you implying. Just tell us that he was unable to do it.

Haha, his load tester was by far the best home made load tester I ever saw.

[quest for silence]

I do not know what to say at this .....

Nothing, just accept it: The Mask has been well clear and very understandable.

Saying that something is not repeatable does not mean that it's not right: but the problem is apparent if and when the relevant results were clearly not congruent.

Okay, that tells us that he was not able to make a dc load.

That tells us now you're acting needlessly polemically (working off some private grudge, perhaps?): and eventually that may turn out as acting stupid, so be careful.

[ITelektro]

Nothing, just accept it: The Mask has been well clear and very understandable.

I'm sorry but I do not accept someone's opinion without a logical, practical, mathematical explanations just like that.
The contested statement is nothing more than just an opinion based on a representative sample of the one unit whitch does not work well, that is apparently wrong.

That tells us now you're acting needlessly polemically (working off some private grudge, perhaps?): and eventually that may turn out as acting stupid, so be careful.

There is no problem if turns that I am wrong, on the contrary will know one thing more.
Here are the facts;

With a homemade tester that's not possible. Aris knows because his first load tester was a homemade load tester.

Aris home made dc load is not working as it shoud, obviously. It is not personal attack on Aris, it is fact that Aris did not made dc load that work as it shoud.
The conclusion, therefore, that none dc load is not working as it shoud is wrong and baseless, it is logical mistake.

[rafal_iB_PL]

He said that the results from one tester cannot be replicated on another tester. It's a valid claim, though not very meaningful to me. It's like saying different PC configurations can give you different FPS in the same game.

After all various loads can be resistive/capacitive/inductive in varying proportions. The way you take readings also matters.

[ITelektro]

He said that the results from one tester cannot be replicated on another tester. It's a valid claim, though not very meaningful to me. It's like saying different PC configurations can give you different FPS in the same game.

Its not good example. If the test conditions, metodology, accuracy are same , measured result will be same. Thats way I put example of 1A on the table.
Different PC cofiguration means different test condition.
After all thats is reason why testing PSU on the PC configuration is not so good idea.

After all various loads can be resistive/capacitive/inductive in varying proportions. The way you take readings also matters.

I agree...but we are discuss here about DC load. Its represents resistive load in CC mode.

From what I read till now it is no point to continue discussing.When I made DC load i checked twice resoults and compare with my Maynuo DC load(Accuracy 0.03%+0.05%FS). I will do it again and post here.

[ITelektro]

Maybe the explanation is simple…there is growing competition of ppl with home-made HW producing high-quality articles.

Example?

They are starting to loose readers so they came up with this, which, translated, reads as "we, and couple others who have big money to buy branded stuff, are the only good ones so don't read the others".

One of the options.
The second is that the author simply made a mistake. I think that's the reason.
We all make mistakes, somebody accept the mistake, correct it ,learns from it .... somebody does not.
This mistake unjustifiably discredit those who do not have mentioned equipment. This is why need to be discussed.
On the other hand this must be checked, maybe he is right.

With high power resistors the transient test can be done equaly good. It also applies almost instant load for the PSU.

Somehow I missed this.
I do not see how you will menage to get a slew rate of 1 A/s with resistor based design.

[rafal_iB_PL]

Its not good example. If the test conditions, metodology, accuracy are same , measured result will be same. Thats way I put example of 1A on the table.
Different PC cofiguration means different test condition.
After all thats is reason why testing PSU on the PC configuration is not so good idea.

And how do you ensure "exact same conditions"? Have you considered different PSU samples? For example, if one sample has loose pins (as it happened many times even here, and has been explicitly mentioned in the reviews) and other does not, readings might vary significantly, even on the very same configuration. So if not all reviews are using the same samples, what do you do? Pick one to be valid and discard all others?

[ITelektro]

And how do you ensure "exact same conditions"?

Hint : 1A example.

Have you considered different PSU samples?

That has nothing with same test conditions.

For example, if one sample has loose pins (as it happened many times even here, and has been explicitly mentioned in the reviews) and other does not, readings might vary significantly, even on the very same configuration.

Yes, I agree.

So if not all reviews are using the same samples, what do you do? Pick one to be valid and discard all others?

IMO: Results you get for one sample is result of that sample unit.
Scientific approach uses the term representative sample.
If you want to give a relatively accurate conclusion for all units then you have to have a representative sample and take an average.
It is not convenient, so it's good to have as many people do review of power supply, so we can get a more reliable conclusion.