Author Topic: EEVblog #512 - Rigol DP832 Bad Design Investigation  (Read 243102 times)

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Offline jsykes

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #400 on: September 21, 2013, 03:19:03 am »
I couldn't wait. Found a nice heatsink I didn't use and inside it went. Mounted the TO220 lm317 isolated on the heatsink and it mates with the PCB using a small cable and pcbmount connector. Now at power on for about an hour the heatsink does barely even feel warm.

GREAT JOB!
That's exactly what I had in mind and the PC mount connector is a nice touch. Luckily I held off purchasing my PS until it was out there a while in case any hardware problems were discovered :phew:  I still may not be satisfied with Rigol's solution if it runs hotter than I'm comfortable with and in that case, will duplicate your method. It's good to see that there is room for that heat sink in the chassis and it looks like it's in the air flow too.
Thanks for passing this on.
« Last Edit: September 21, 2013, 03:21:45 am by jsykes »
 

Offline stormbr

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #401 on: September 21, 2013, 07:11:17 am »
Excellent solution nack.

Thanks for share.

 

Offline Zbig

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #402 on: September 21, 2013, 07:53:30 am »
Had I got a DP832, I'd definitely cut a circular hole in the top of the case, mount an aluminum plate in it and bolt the regulator on the underside. TADAAA! A coffee warmer!

I know, I know, thank you, you're welcome!
 

Offline John South

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #403 on: September 30, 2013, 12:52:35 pm »
Hi - I have some pictures of the new boards.

For Australia and New Zealand customers we are expecting the new boards to be leaving China around October 17th. I'm not sure on the rest of the world.

Disclosure : I work for Emona Instruments. We are a supplier of T&M equipment in Australia and are the Australian Distributors for Rigol. www.emona.com.au/rigol
 

Offline mariush

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #404 on: September 30, 2013, 01:11:31 pm »
Hmm... seems so weird of a fix to me. 

That heatsink is so large it looks like it blocks airflow...
It looks like there may be issues with the weight coupled with vibrations and shocks making solder joints weak...
Seems like there's enough room so they could have put there a regulator to get the voltage down to 6-7v, then use second regulator to get 5c and spread the heat on two heatsinks.
 

Offline ddavidebor

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EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #405 on: September 30, 2013, 03:49:49 pm »
Or design a little switching one on board.
Davide Bortolami,
Fermium LABS srl
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #406 on: September 30, 2013, 04:40:42 pm »
That heatsink is so large it looks like it blocks airflow...
It looks like there may be issues with the weight coupled with vibrations and shocks making solder joints weak...
Seems like there's enough room so they could have put there a regulator to get the voltage down to 6-7v, then use second regulator to get 5c and spread the heat on two heatsinks.

There are plenty of vents before and aft of the heatsink, so airflow shouldn't be restricted.
A heaksink that size will be firmly soldered the board just like the other ones, so should be no vibration issues.
 

Offline unnecessarynitpicker

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #407 on: September 30, 2013, 11:09:27 pm »
It looks like they replaced the coffee maker heat sink as well as another one of the small ones to a slightly thicker variety (the new heat sinks are silver and not black) but i guess that we are all wondering is what happens when you turn it on instead of taking it apart :P.
 

Offline nack

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #408 on: October 01, 2013, 07:30:49 pm »
LM317's (ST brand) I have bought recently also have the new thin-style tap design. Copper is expensive these days I presume...
 

Offline os40la

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #409 on: October 03, 2013, 09:26:19 am »
Placed an order for a DP832 from TEquipment today. Thanks Dave for the EEVBLOG discount!  :-+ Waiting for the heatsink fixed ones to come in.
« Last Edit: October 03, 2013, 09:28:09 am by os40la »
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Offline Monkeh

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #410 on: October 03, 2013, 09:39:34 am »
I wonder if they have switched to a different regulator as well? Even if it is still an LM317 the one they used seemed a bit odd, like the tab was unusually thin.

That's been covered already, the thin tab is pretty normal from ST.
 

Offline os40la

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #411 on: October 04, 2013, 07:53:06 am »
Does anyone how to configure the DP832 to get +12v,-12v and 5v? I know how to configure it to get +12v and -12v since channel 1 is isolated. But is there a way to get channel 3 to output +5v at the same time (with all common grounds)? For example to power a op amp. Or can't it be done on the DP832?  :-//
"No, but I did stay at a Holiday Inn Express"
 

alm

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #412 on: October 04, 2013, 07:56:57 am »
Outputs 2 and 3 share a common negative terminal, so setting output 1 to 12 V, output 2 to 12 V and output 3 to 5V and connecting the positive output of output 1 to the negative output of outputs 2 and 3 should give you -12 V from the negative output 1 terminal, +12 V from the positive output 2 terminal and +5 V from the positive output 3 terminal, referenced to the output 2/3 negative terminal.
 

Offline os40la

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #413 on: October 04, 2013, 10:12:50 am »
Outputs 2 and 3 share a common negative terminal, so setting output 1 to 12 V, output 2 to 12 V and output 3 to 5V and connecting the positive output of output 1 to the negative output of outputs 2 and 3 should give you -12 V from the negative output 1 terminal, +12 V from the positive output 2 terminal and +5 V from the positive output 3 terminal, referenced to the output 2/3 negative terminal.

Got it. Thanks for clearing that up. :-+
"No, but I did stay at a Holiday Inn Express"
 

Offline nack

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #414 on: October 04, 2013, 07:23:41 pm »
Looks like the sense wiring in the unit isn't designed that thoughtful:

« Last Edit: October 04, 2013, 07:48:59 pm by EEVblog »
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #415 on: October 04, 2013, 07:53:36 pm »
Looks like the sense wiring in the unit isn't designed that thoughtful

Oops!  :-[
Issue reported.
 

Offline BravoV

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #416 on: October 04, 2013, 07:59:06 pm »
So Rev 5  ?  ???

Offline hikariuk

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #417 on: October 04, 2013, 09:07:05 pm »
Looks like the sense wiring in the unit isn't designed that thoughtful...

I like his way of testing for >= 100C.
I write software.  I'd far rather be doing something else.
 

Offline jancumps

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #418 on: October 04, 2013, 09:34:19 pm »
Looks like the sense wiring in the unit isn't designed that thoughtful...

I like his way of testing for >= 100C.
i have 1 2n3055 lying here with my fingerprint on it forever from trying to check if it was getting hot with my index finger.
 

Offline grego

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #419 on: October 05, 2013, 12:14:53 am »
Yeah Rigol needs to fix the sense wire issue.  However, at least this is something easily fixed "in the field".  That doesn't excuse it and I hope it's either already fixed on the new rev or fixed with another rev soon.
 

Online Fraser

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #420 on: October 05, 2013, 01:22:43 am »
The faults being discovered in this unit are just so basic that I wonder what experience the design team had (students ?) and who they employed for product UAT. Whoever it was, they need to find a new person !

Rigol really are sullying this power supplies reputation....if not already, it will become infamous and the butt of jokes in the industry. A good example to show to EE Students at college ....... how NOT to design a precision power supply  :-BROKE
 

Offline railman

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #421 on: October 07, 2013, 10:44:01 am »
I wonder if all this PR has hurt or helped Rigol. Or has it made the DP832 the best power supply on the market for the money?
 

Offline EEVblog

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #422 on: October 07, 2013, 10:51:15 am »
Rigol really are sullying this power supplies reputation....

Either that, or (once they fix everything) the best vetted supply in the industry?
 

Offline AndyC_772

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #423 on: October 07, 2013, 05:45:40 pm »
Maybe, but the more I hear about this unit, the more I like the HP 6632B's I picked up off Ebay.
 

Online Fraser

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #424 on: October 07, 2013, 08:33:02 pm »
Dave,

A very good point. Rigol effectively have the largest UAT test that you could wish for. They are also having all the bugs pulled out by a group of very knowledgeable people FOR FREE !

That all sounds good but it is happening in public and you guys will not always be available to pull the bugs out of their products so doubt will exist when they release their next product ?

Now if Rigol had been smart, they would have done UAT and hardware testing in the same way as software is done. Alpha and Beta testers. An opportunity for paid consultancy Dave ? You know what the market needs and know how to test the product for performance. You are also independent of the companies design team.   
 


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