Author Topic: EEVblog #512 - Rigol DP832 Bad Design Investigation  (Read 244544 times)

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Offline TooOldForThis

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #450 on: October 18, 2013, 01:48:50 pm »
Does anyone know if the DP832 can have its channels 1 & 2 wired in parallel to give 0-30v at up to 6 amps?  There is a tracking function that keeps the two channels at the same voltage but the user manual doesn't say anything for or against hooking the channels up in parallel. 
 

Offline Sparky

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #451 on: October 18, 2013, 02:06:01 pm »
Does anyone know if the DP832 can have its channels 1 & 2 wired in parallel to give 0-30v at up to 6 amps?  There is a tracking function that keeps the two channels at the same voltage but the user manual doesn't say anything for or against hooking the channels up in parallel.

Yep, you can wire it up like that in tracking mode for 6A output.
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #452 on: October 18, 2013, 10:43:05 pm »
Does anyone know if the DP832 can have its channels 1 & 2 wired in parallel to give 0-30v at up to 6 amps?

Read the attachment to have confirmation from Rigol.



I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline Zbig

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #453 on: October 19, 2013, 01:19:53 am »
Does anyone know if the DP832 can have its channels 1 & 2 wired in parallel to give 0-30v at up to 6 amps?  There is a tracking function that keeps the two channels at the same voltage but the user manual doesn't say anything for or against hooking the channels up in parallel.

Well, as they're in parallel, the voltage is always going to be equal anyway, right? What I believe the tracking function does when in parallel mode is, it reads the master channel's current readout and applies it as current limit to the slave channel working in CC mode. It's the serial mode where the slave channel's voltage simply follows master channel's voltage.
 

Offline mcinque

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EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #454 on: October 19, 2013, 03:35:18 am »
As I l know the tracking is used to power up symmetrical devices like dual amplifiers
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline ddavidebor

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #455 on: October 23, 2013, 01:40:20 am »
or to use channel in parallel
Davide Bortolami,
Fermium LABS srl
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #456 on: October 30, 2013, 11:08:19 pm »
nope...  :-//
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline con-f-use

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #457 on: October 30, 2013, 11:14:29 pm »
Not a thing.
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #458 on: November 01, 2013, 08:11:59 pm »
Attached is the response from Rigol on the DP832 connection issue.
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #459 on: November 01, 2013, 08:13:24 pm »
Anyone heard anything about the recall yet? Particularly people in Europe. I have heard nothing.

Emona in Oz have received replacement boards and instructions, but still sorting out the recall/repair logistics.
 

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #460 on: November 02, 2013, 01:26:21 am »
Attached is the response from Rigol on the DP832 connection issue.
Translation: we have no intention of fixing this. The user should just refrain from connecting CH2 and CH3 as would be obvious from the front panel silkscreen. If you want the power supply to work within specs while treating CH2 and CH3 as having a common ground, please do our job and put the thick wire between the CH2 and CH3 negative terminal that should have been there in the first place.
 

Offline Rufus

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #461 on: November 02, 2013, 01:36:09 am »
Attached is the response from Rigol on the DP832 connection issue.

Shame they put less thought into the original power supply design than they put into that document.
 

Offline daveshah

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #462 on: November 02, 2013, 04:09:14 am »
Attached is the response from Rigol on the DP832 connection issue.
Rigol are obviously using the state of the art in multimeter technology, as is evident on page 3!
 

Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #463 on: November 02, 2013, 05:21:43 am »
Regarding the fix...

I tried to contact Rigol a few times by email and the contact form and never got any reply.

So I sent an email to TEquipment (where I bought it).  Jennifer there was very helpful and said she will get in touch with Rigol and figure out what is going on for replacing faulty DP832 units/boards for USA customers.

I haven't heard back yet, but I told her it was not a big rush, just wanted to make sure it doesn't get forgotten or swept under the rug.

So far I am less than impressed with Rigol, but very impressed with TEquipment.  Which is why I keep going back (Scope, FLIR camera, etc).

Rigol could learn a thing or two about customer service. 
It's not always the most popular person who gets the job done.
 

Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #464 on: November 02, 2013, 09:20:28 am »
Just to post an update to my post above - I have to soften my criticism for Rigol a bit.  I got a call from a guy there today - nice guy and he explained that the DP832 did have an issue and they were replacing boards on USA units.  Apparently they are waiting on a shipment of repair parts from the China factory.

I don't think anything they told me was a secret, but basically they are keeping a list of USA customers who need repairs on their units.  They will then be contacting us when it's time to send our units in.

More info here:

http://beyondmeasure.rigoltech.com/acton/fs/blocks/showLandingPage/a/1579/p/p-0011/t/page/fm/0

There is a link on the above page to here;

http://beyondmeasure.rigoltech.com/acton/form/1579/0014:d-0001/1/index.htm

where you can fill out your info to get on their repair list (for USA customers only), and there is also a specific email address for USA customers inquiring about DP832 repair, that address is dp8repairusa@rigol.com

So if you are in the USA, fill out the form and then wait to hear back from Rigol.

I was told that my unit was the first one they have heard about having resetting issues (which only happens when I make it happen - i.e. put it in my rack, load it up and suck power from USB as well)... so to be fair, it's not like it resets all the time, but it does run hot as hell, measured way over 250F with my FLIR camera, so it definitely needs the upgraded board.

Just an FYI!
It's not always the most popular person who gets the job done.
 

Offline Dave Turner

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #465 on: November 08, 2013, 07:52:03 am »
I received my DP832 and DS1074Z-S today. Ordered from Rigol's UK distributor Telonic Instruments less than 48 hours after ordering. It does have to be said that they seem to be both helpful and efficient.

Having said that, even after discussing the issues reported in this forum, and in particular describing the larger un-anodised as opposed to the intermediate black heatsink, I have received the latter. I have mentioned this to Telonic and await a reply.

Unfortunately my temperature probe is too large to fit through the ventilation holes to measure the temperature. I await delivery of a new multimeter with a smaller probe.

Without anything to compare it to (and for many years having worked in a server room) I would not consider the fan noise excessive. Still I've not yet applied a serious load.

For interest the Serial number is DP8C15320xxxx and the firmware version 00.01.06.
 

Offline TooOldForThis

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #466 on: November 08, 2013, 01:44:39 pm »
Interesting (maybe) tidbit:  When the DP832 has channels 1 & 2 hooked in parallel, it will max out one channel before supplying any power from the 2nd channel.  If you pull 3.1 amps, ch1 supplies 3.0A and ch2 supplies 0.1A   On my older analog controlled supplies, both channels will split the load 50/50. 

Update: Different results reported 8 posts down.
« Last Edit: November 09, 2013, 11:44:47 am by TooOldForThis »
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #467 on: November 08, 2013, 08:09:32 pm »
Here are photos of the replacement board:
http://www.flickr.com/photos/eevblog/sets/72157637434451504/
 

Online dr.diesel

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #468 on: November 08, 2013, 09:47:22 pm »
Here are photos of the replacement board:
http://www.flickr.com/photos/eevblog/sets/72157637434451504/

lol, that's a hell of a heat sink for a TO-220!

Online Fraser

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #469 on: November 09, 2013, 12:29:35 am »
Hmmmm...cheap and nasty fix  :--

Better regulator fitment would have been preferable but I suppose it all comes down to money when all is said and done.
« Last Edit: November 09, 2013, 01:33:23 am by Aurora »
 

Offline ddavidebor

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EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #470 on: November 09, 2013, 01:09:43 am »
If they had managed better those issue, i woukd have bought a rigol instead of a hameg
Davide Bortolami,
Fermium LABS srl
 

Online dr.diesel

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #471 on: November 09, 2013, 01:29:09 am »
Hmmmm...cheap and nasty fix  :--

Agreed.  Although it screams poorly designed by an intern, it will allow the unit to live for years most likely.


If they had managed better those issue, i woukd have bought a rigol instead of a hameg

Which model, please do a mini-review/teardown for us!

Offline Cdngreybeard

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #472 on: November 09, 2013, 02:15:50 am »
For TooOldForThis:
The DP832 does load share when paralleling ch 1 and ch 2.  The load will split more or less equally based upon the lead resistances to the two supplies.  Cosequently, the higher the current draw, the greater the discrepancy. I have verified this with a 1 ohm load at 5 volts resulting in current draws of 2.6 A and 2.4 A respectively.

 

Offline ElectroIrradiator

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #473 on: November 09, 2013, 03:16:09 am »
lol, that's a hell of a heat sink for a TO-220!

Bonus silly points: The air cooling would have worked much better with a new profile, if they had just used a vertical metal plate parallel to the main heat sink, along the board. As it is, the new (huge) heat sink sits 'fins down' into the oncoming air stream, the worst possible option. Translation: Whomever devised this, didn't seem to understand the principles of forced air cooling. :palm:
 

Offline TooOldForThis

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #474 on: November 09, 2013, 11:37:36 am »
For TooOldForThis:
The DP832 does load share when paralleling ch 1 and ch 2.  The load will split more or less equally based upon the lead resistances to the two supplies.  Consequently, the higher the current draw, the greater the discrepancy. I have verified this with a 1 ohm load at 5 volts resulting in current draws of 2.6 A and 2.4 A respectively.

I was able to reproduce this result.  I had a 20mV loss on the banana jumpers connecting Ch1 to Ch2.  The channel with less loss to the load wound up driving the majority of the current.  When I connected both channels to the load symmetrically,  then both channels shared the load more or less evenly.   My older supplies have an internal relay for parallel mode that short the two channels together with low enough resistance that both channels supply the same current no matter how I hook it to the load.   
 


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