Author Topic: EEVblog #512 - Rigol DP832 Bad Design Investigation  (Read 255508 times)

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Offline AndersAnd

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #500 on: November 26, 2013, 01:33:21 pm »
Still nothing for EU owners. I emailed them again, no response.
Who did you e-mail, http://eu.rigol.com or a European distibutor?

Both.
What distributor is that?
 

Offline synapsis

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #501 on: November 30, 2013, 12:19:41 am »
Order a DP832 from Rigol directly last week. Got this on the second powerup, I've never plugged anything into the outputs yet.

I can see the tall silver heatsink inside the unit.

*sigh*
 

Offline synapsis

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #502 on: November 30, 2013, 12:35:22 am »
Turned it on again and the now the contrast on the LCD flickers.
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #503 on: November 30, 2013, 09:28:28 am »
Call distributor and get a RMA.
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshits
 

Offline Skimask

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #504 on: December 03, 2013, 06:42:24 am »
Just got my new DP832 on my door step today.  (Backstory - Ordered one, got it early November, Channel 1 failed after a dozen or so uses, RMA'd for replacement last week)
Ordered direct from Rigol NA.

Old one firmware = 1.06, new one = 1.08

Old one had the "middle design", new has the new PCB with the large aluminum heat sink.

Beating it up a bit right now, trying (not too crazy hard anyways) to get it to fail now rather than later...  Gonna do this for a couple hours or so.
Got all 3 channels pushing 3 space heaters coils.  Ch1&2 @ 27v @ 2.7amps, Ch3 @ 5v @ 2.7amps.  About 160 watts.
Going over to the box every 10-15 minutes or so, switching it off, waiting a minute, switch it back on, and enable all 3 outputs at the same time (or as close to it as I can get).
Every 2nd or 3rd time, I'm waiting a minute after turning them on, switch all 3 outputs off, then right back on.
Got meters on the outputs watching volts/current.  DP832's LCD and the BK2709's match up pretty good.
So far, so good...
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline Dave Turner

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #505 on: December 13, 2013, 07:15:35 pm »
Further to my previous post, Dave of Telonic Instruments Ltd the official Rigol distributor in the UK contacted me today to inform me that they are expecting the latest version of the DP832 in February. They have offered to swap out my DP832 for the latest model, including carriage both ways.

It should be pointed out that I had discussed and clearly pointed out the findings of this forum and my expectation to receive the latest version, the one with the overgrown silver heatsink, before I placed my order. (All by phone). Unfortunately that was not the model that I received; a fact that I immediately reported to Telonic.

I have offered to just swap out the board myself providing that they will accept my breaking the seal without affecting my warranty. This would be easier for me and might be cheaper for Telonic who seem to be amenable to this solution.

We have agreed to wait until February when the new versions are available before making a final decision on how to proceed.

Whilst nothing has been resolved yet, given the service I have received so far I wouldn't hesitate to recommend Telonic.

For the record I have no connection to Telonic and this is the first time I have purchased anything from them.
 

Offline Timon

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #506 on: January 02, 2014, 05:22:41 pm »
Maybe someone has brought this up but why the heck didn't they use something like a OKI-78SR switching regulator? They are very inexpensive and they don't even need a heat sink to deliver 1.5A. In addition you can easily retrofit it.
« Last Edit: January 02, 2014, 05:24:50 pm by Timon »
 

Offline mariush

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #507 on: January 02, 2014, 06:18:10 pm »
Adding a bit of copper wire on an already custom transformer is cheaper than one of those custom switching regulators.  They just screwed up by making that winding 10-12 v AC or whatever it was

Copper on transformer + bridge rectifier and capacitors and lm317 < 1$ ... that oki regulator, probably 2-3$.
 

Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #508 on: January 09, 2014, 02:27:54 am »
So here is my timeline...

Purchased DP832 in July of 2013.

Found out about the issue from Dave in late August 2013.

Contacted Rigol in September 2013 asking about a fix.  Contacted them several times and never got any reply.

In October, I contacted TEquipment asking for help.  They intervened and finally someone at Rigol got in touch and said they would fix my unit, and they had a sign-up list.  That was in late October 2013.

It is now January 2014 and still nothing has been done.  It's starting to piss me off that Rigol has been selling fixed units for months, but hasn't made things right with prior buyers.  Frankly, fixing existing units should have been the #1 priority, not selling new ones while they let the early adopters deal with dysfunctional supplies.


Has anyone in the USA had their DP832 fixed by sending it back to Rigol for repair?  I just tried emailing them again - we shall see what happens.
It's not always the most popular person who gets the job done.
 

Offline Sparky

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #509 on: January 09, 2014, 07:00:22 am »
Has anyone in the USA had their DP832 fixed by sending it back to Rigol for repair?  I just tried emailing them again - we shall see what happens.

I'm in similar situation --- I filled out the Rigol online form to get put on a list for the replacement board, but I haven't heard anything from them yet.

I'm using my unit frequently and without troubles at the moment so I'm not worrying much about it.  Also, I think I recall some photos of Oct/Nov DP832 units sold in the US having the "medium" sized heatsink, and not the extra large (silver) heatsink, installed...so I don't want to rush through an upgrade program only to have an incorrect replacement board fitted.  I don't know the potential of that happening...but just want to avoid it...

Would be nice to have some update from Rigol NA though --- if you do hear back, it'll be great to hear what you find out.
 

Offline ivaylo

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #510 on: January 09, 2014, 08:47:31 am »
I told Tequipment I want to return mine. They defered to Rigol. I got a RMA and shipped it back yesterday. I had DP832A and the low current resolution was important to me (but broken). Got a refurbished Hameg instead from someone here on the forum.
 

Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #511 on: January 09, 2014, 04:55:46 pm »
I sent a polite email to "info@rigol.com" last night stating the timeline of my issue and asking for either a fix or at least information on when the fix would be offered.  I received an email back a few hours ago from a gentleman at Rigol who sent an RMA form and a pre-paid return shipping tag.  He mentioned they had been kept waiting for the repair parts, and that it was taking time to work through the backlog of units for repair. 

At least it appears they are now performing the fixes - hopefully the turnaround time won't be too bad.  I have other supplies I can use so I won't miss this one for a couple of weeks, but I hope it doesn't end up taking a couple months.  I don't think it will - they told me they should be able to turn it quick.

So for anyone still waiting, I guess you could either wait for contact knowing they are doing fixes, or you could email info@rigol.com and ask them to ensure you are on the list, at least.

Hope it helps.
It's not always the most popular person who gets the job done.
 

Offline K1JOS

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #512 on: January 17, 2014, 02:00:18 am »
Is the heatsink design an issue only on the non-A832 or also the 832A?
jerry
 

Offline ivaylo

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #513 on: January 17, 2014, 05:55:48 am »
Both. It's supposed to be fixed in the new versions though.
 

Offline Rasz

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #514 on: January 17, 2014, 10:42:37 am »
Adding a bit of copper wire on an already custom transformer is cheaper than one of those custom switching regulators.  They just screwed Copper on transformer + bridge rectifier and capacitors and lm317 < 1$ ... that oki regulator, probably 2-3$.

Because $2 of short term profit is better than good quality product, obviously :/
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My fireplace is on fire, but in all the wrong places.
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #515 on: January 17, 2014, 12:44:55 pm »
Just to inform all Italian customers that my local dealer, Batter Fly srl (www.batterfly.com), is ignoring my mails about the DP832 since december 2013. I am also unable to reach the CEO by phone.

I am seriously starting to concern about my Rigol instruments warranty. I was confident to have found a loyal distrubutor. At the moment I cannot think so.


EDIT: they finally reply to my mails, saying that the delay was because they're moving on another location and that the DP replacement will be made as soon new units will be available.
« Last Edit: January 19, 2014, 10:27:57 pm by mcinque »
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshits
 

Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #516 on: January 17, 2014, 10:59:48 pm »
Adding a bit of copper wire on an already custom transformer is cheaper than one of those custom switching regulators.  They just screwed Copper on transformer + bridge rectifier and capacitors and lm317 < 1$ ... that oki regulator, probably 2-3$.

Because $2 of short term profit is better than good quality product, obviously :/

That's a foolish analysis.

If they were going for short term profit, they wouldn't be taking them back and replacing parts at no charge.  I bet the repair on my DP832 costs Rigol more than their profit on the unit amounted to. 
It's not always the most popular person who gets the job done.
 

Offline rsivan

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #517 on: January 17, 2014, 11:30:21 pm »
Hello to all I play little with dp832, already have rev 2.10 fixed board but not with big heatsink and after some tests  I replaced the lm317 with home made L5972D 1.5A high efficency switching step-down,it  works fine I also removed smd resistor load 240ohm on 12v before lm317 , I used diagram from datasheet with 10uf ceramic cap on 12v 33uH smd inductor and tantalium cap on 5v out,temp on lm317 was 85c and about 5.14V , now I calibrated with 5.08V,the new temp stay at 36c on my little pcb.
 I replaced also fan with noctua, very quiet now but need also to decrease R50 from 2.4k down to 1.8-2.0k to avoid fan error, because noctua drain less current and trigger error when at idle,I tested with all 3 channel at max load and cooling is good we will see in the summer if go fire.
« Last Edit: January 18, 2014, 12:07:26 am by rsivan »
 

Offline AndersAnd

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #518 on: January 18, 2014, 12:23:02 am »
I replaced the lm317 with home made L5972D 1.5A high efficency switching step-down,it  works fine I also removed smd resistor load 240ohm on 12v before lm317 , I used diagram from datasheet with 10uf ceramic cap on 12v 33uH smd inductor and tantalium cap on 5v out
So this is the schematic you used I guess? Of course with the R1 and R2 resistor divider changed to get Vout = 5 V.


Image source: http://xinyeic.en.seekic.com/product/integrated_circuits_ics/L5972D.html

ST L5972D datasheet: http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00002850.pdf
ST Application Note AN1517 http://www.st.com/st-web-ui/static/active/cn/resource/technical/document/application_note/CD00043743.pdf
There's very little documentation in the datasheet so check out AN1517 for the L5972D demo board. AN1517 contains a lot of info that usually belongs in datasheets.
« Last Edit: January 18, 2014, 12:50:57 am by AndersAnd »
 

Offline rsivan

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #519 on: January 18, 2014, 12:28:58 am »
yes changed resistor for 5.088V  I alredy have this pcb build for test this ic I used on other design you can also see mosfet sot23 to control on-off but tied 12v enable wire and not used
 

Offline Rasz

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #520 on: January 18, 2014, 05:24:02 am »
Adding a bit of copper wire on an already custom transformer is cheaper than one of those custom switching regulators.  They just screwed Copper on transformer + bridge rectifier and capacitors and lm317 < 1$ ... that oki regulator, probably 2-3$.

Because $2 of short term profit is better than good quality product, obviously :/

That's a foolish analysis.

If they were going for short term profit, they wouldn't be taking them back and replacing parts at no charge.  I bet the repair on my DP832 costs Rigol more than their profit on the unit amounted to.

This is just post facto saving ones ass. They would made $2 more if not for those meddling kids (Dave)!
Do you really believe an engineer decide to use 317 there on purpose while listening to ?Or that he was ordered to make it cheap?
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My fireplace is on fire, but in all the wrong places.
 

Offline ted572

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #521 on: January 18, 2014, 03:19:54 pm »
Please, can someone tell me if upgrading the DP832 Firmware to 00.01.08.00.02 works OK without corrupting anything with one or more of Options activated.
 

Offline rsivan

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #522 on: January 18, 2014, 03:21:30 pm »
I upgradet from 1.06 to 1.08 lost only advanced Trigger option also you need to do recalibration
 

Offline ted572

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #523 on: January 18, 2014, 03:40:20 pm »
I upgraded from 1.06 to 1.08 lost only advanced Trigger option also you need to do recalibration
I was hopping that if the Rigol FW Upgrade Procedure was followed that Re-Cal would not be required.  This procedure is much more involved than the normal FW Upgrade, as it is applied to three (3) separate PCB assemblies is succession.

Note: I had not seen the DP832 FW Installation Procedure on the Rigol web site.  So I thought that there was a good possibility that other people doing the FW upgrade hadn't either, and that perhaps this was the reason that their upgrade to to FW 08 wasn't fully successful(?).

Did you know about this procedure (attached below)? 
Did you have to go through the complete Rigol Cal Procedure for the DP832?  And if so, about how long does it take?
Sorry for all the questions, and thank you very much for your assistance.   
« Last Edit: January 18, 2014, 04:19:42 pm by ted572 »
 

Offline ted572

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #524 on: January 18, 2014, 07:15:10 pm »
I upgradet from 1.06 to 1.08 lost only advanced Trigger option also you need to do recalibration
rsivan:  I didn't hear back from you with answers to my questions, so I went ahead and upgraded to FW 08.

I lost the 'Trigger' Option as you had, but Calibration was not affected.  So I'll call this a success, with the loss of Trigger as a secondary or worthy sacrifice for the other benefits.
I tried reinstalling Trigger, but I get an 'invalid key' response.  It worked in FW 06, so apparently there is an issue with the Trigger key, the Trigger option changing, or otherwise being disabled in FW 08.
 


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