Author Topic: Project Yaigol: Fixing Rigol scope design problems.  (Read 79616 times)

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Offline wraper

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #75 on: March 16, 2016, 06:10:06 am »
Yaigol use 1117 adjustable type of regulator, so there is a voltage setting resistor divider with it. Replacing the regulator will require removing the divider or replacing with a new one depending if your new regulator is of a fixed or adjustable type. In both cases i'd think it is not necessary, just do a simple capacitor swap and you will be fine.
Actually not, there is NCP1117 3.3V fixed type on your photo. Even if it was adjustable, no resistor change would be needed as vast majority of LDOs have the same reference voltage.
 

Offline SaabFAN

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #76 on: March 16, 2016, 06:56:13 am »
Well, I guess THAT flushes even the very last moral obstacle against hacking Rigol-Stuff down the toilet.
I certainly don't feel bad about them at all anymore and just added the necessary components to my next Digikey-Order. ^^

Is there a possibility to give the PLL some "proper" values? If I understand it correctly, the Jumpers can be used to disconnect the PLL from the rest of the SPI-Bus.
Should be possible to put a Attiny in there to program the PLL with the right values upon power-up.
Unless the scope is doing some tricky stuff with the PLL under certain operating conditions.

Btw. isn't there a Rigol-Representative here on the Forum? I wonder what he has to say about this apparent aversion to reading the datasheets :)

Offline Bud

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #77 on: March 16, 2016, 03:51:40 pm »
Yes it is possible to control the PLL with your own microcontroller. No the scope did not seem to reprogram the PLL during operation, only programmed the registers at power on.
 

Offline Mr.B

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #78 on: March 16, 2016, 04:08:36 pm »
Bookmark...
Thank you for going to the trouble of doing all this.
Time is the overseer of all things.
 

Offline Bud

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #79 on: March 16, 2016, 05:55:55 pm »
Thank you and enjoy Part 4.
 

Online tautech

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #80 on: March 16, 2016, 06:40:21 pm »
And I am tired to tell you what I think about Yaigol. This time I am going to ask you to tell me what
you think about their level of competency and if their Yingineers read Datasheets.
Maybe they've used one of their own DSO's to confirm their PSU designs and the oscillations/ripple is invisible to it?  ;)

For those watching Bud has offered his Yaigol DSO in the Buy/Sell thread:
https://www.eevblog.com/forum/buysellwanted/fs-rigol-ds2072a-oscilloscope-300mhz/

Has it had all the fixes to date Bud?
« Last Edit: March 16, 2016, 06:45:57 pm by tautech »
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Offline nctnico

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #81 on: March 16, 2016, 07:20:38 pm »
Thank you and enjoy Part 4.
All LDOs are oscillating?  Yikes!  :palm:
I'm wondering how they missed that during development. The first time I used an LM1117 I spotted it was oscillating pretty quick and that was only one device. Or have the designers put in the right component and got it replaced by something 'compatible' by the procurement department?
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline EV

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #82 on: March 16, 2016, 07:20:57 pm »
Thanks Bud! Great work!
 

Offline kripton2035

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #83 on: March 16, 2016, 07:32:02 pm »
Thank you and enjoy Part 4.
I enjoyed reading part4 as well as all the previous parts
my thoughts : you deserve to sell your scope at a higher price than a new one !

Offline Mr.B

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #84 on: March 16, 2016, 07:34:53 pm »
@Bud -
Have you approached Rigol about this?
Pointed them at your thread?

You have done a lot of hard work here and they should be grateful.
Perhaps they will take notice and modify for Rev 2...

I have a 2072...
I don't know whether to make your mods or not... (I have the skills and tools to do direct replacements, no way of getting the inductors tuned correctly though.)
I don't know whether to contact Rigol and make a formal complaint...
Hmm... A bit confused as to what I should do.
Time is the overseer of all things.
 

Online hendorog

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #85 on: March 16, 2016, 07:41:17 pm »
This is really nice work, and interesting. Thanks for taking the time to document it all Bud. However one thing is bothering me.

What effect do these issues have on the actual usage of the scope?

It would be interesting to compare Buds improved scope with an original to see what the differences are in actual use.
 

Offline AndyC_772

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #86 on: March 16, 2016, 07:48:33 pm »
I was wondering about that too. Clearly there's some design errors in the scope, but it would be interesting to see how they affect the actual displayed waveform on screen under various conditions.

I think it would be useful for anyone with an affected scope to know when - or, indeed, if - they are likely to see artefacts that relate to these issues, and what relevant, quantitative improvement they'd see by opening up the scope and applying the fixes.
 

Offline Mr.B

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #87 on: March 16, 2016, 07:56:37 pm »
+1

Thats why I am at a loss as to whether to do anything about it...
Time is the overseer of all things.
 

Online tggzzz

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #88 on: March 16, 2016, 08:00:32 pm »
In the UK you can return the scope to the supplier under the Consumer Rights Act.

After the first six months the burden is on you to prove that the product was faulty at the time of delivery. In practice, this may require some form of expert report, opinion or evidence of similar problems across the product range. You have six years to take a claim to the small claims court for faulty goods in England, Wales and Northern Ireland and five years in Scotland. This doesn't mean that a product has to last six years - just that you have this length of time in which to make a claim if a retailer refuses to repair or replace a faulty product.

FFI: http://www.which.co.uk/consumer-rights/regulation/consumer-rights-act#link-8
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline kripton2035

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #89 on: March 16, 2016, 08:16:11 pm »
Bud lives in canada ...;)

Offline Emi

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #90 on: March 16, 2016, 08:22:12 pm »
Hi..
Bud says  lt1038  is a fixed reg ...
but from ds i assume it's adjustable!
how can he change it on the fly ?
i dont understand this step :-//
« Last Edit: March 16, 2016, 08:25:56 pm by Emi »
 

Online tggzzz

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #91 on: March 16, 2016, 08:23:20 pm »
Bud lives in canada ...;)
Many Rigol purchasers live in the UK.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline nctnico

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #92 on: March 16, 2016, 08:39:58 pm »
+1
Thats why I am at a loss as to whether to do anything about it...
The oscillation in the LDOs is very likely to swing the power supplies out of spec for the devices they power so if you experience random crashes it is a good idea to apply the LDO fixes.
« Last Edit: March 16, 2016, 08:53:56 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online tautech

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #93 on: March 16, 2016, 08:43:39 pm »
+1

Thats why I am at a loss as to whether to do anything about it...
If you don't the uncertainty will nag you till you die.  ;)

+1
Thats why I am at a loss as to whether to do anything about it...
The oscillation in the LDOs is very likely to swing the power supplies out of spec for the devices they power so if you experience random crashes I is a good idea to apply the LDO fixes.
Exactly
« Last Edit: March 16, 2016, 08:45:15 pm by tautech »
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Offline AndyC_772

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #94 on: March 16, 2016, 08:51:50 pm »
I wouldn't personally get my hopes up. A small amount of ripple on a digital supply is unlikely to cause crashes in my experience.

Poor SI on a high speed interface, or buggy code, are far more likely IMHO.

Happy to be proved wrong if someone feels like carrying out a controlled experiment to check.
 

Offline nctnico

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #95 on: March 16, 2016, 08:55:55 pm »
I wouldn't personally get my hopes up. A small amount of ripple on a digital supply is unlikely to cause crashes in my experience.
Expect the oscillation to be in the ballpark of 200 to 300mVpp so it is not a small ripple. On a 3.3V supply it is plain to see with an oscilloscope set to 1V/div.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline AndyC_772

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #96 on: March 16, 2016, 09:07:35 pm »
Expect the oscillation to be in the ballpark of 200 to 300mVpp so it is not a small ripple.

I know the theme of the thread is just how tragically incompetent this board's designer clearly was, but seriously...? Even the most inept amateur would spot that amount of ripple, there's no way it wouldn't be noticed.

Again, equally happy to be proved wrong if someone feels like probing an unmodified scope to check. I don't have one.
 

Online tautech

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #97 on: March 16, 2016, 09:22:59 pm »
Even the most inept amateur would spot that amount of ripple, there's no way it wouldn't be noticed.
And release it into production?
Heaven forbid, in days gone by they'd be out the door.
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Offline IanJ

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #98 on: March 16, 2016, 10:50:43 pm »
Hi all,

Rigol in my opinion will know all about this issue as the scope has been around for a good while, well you would have thought so anyways!.
They will have weighed up everything along the way and risk assessed whether they should have done anything about it.

Great work by BUD though, and you never know as a PR push Rigol might adjust the current BOM in production.

For the rest of us, we can enjoy a home fix courtesy of BUD's great instructions. I'll certainly be looking at it.

Ian.
Ian Johnston
www.ianjohnston.com
Manufacturer of the PDVS2
 

Online tggzzz

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Re: Project Yaigol: Fixing Rigol scope design problems.
« Reply #99 on: March 16, 2016, 11:02:28 pm »
They will have weighed up everything along the way and risk assessed whether they should have done anything about it.

Probably.

One thing that will get their attention is if their distributors find they are having to sort out complaints and court cases from customers.

IANAL, but given Bud's report, I would expect it would be an easy court case to prosecute in the UK's small claims courts.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 


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