Author Topic: EEVblog #512 - Rigol DP832 Bad Design Investigation  (Read 254425 times)

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #325 on: September 05, 2013, 05:15:26 am »
UPDATE:

From John South at Emona:
Quote
Rigol will be replacing the Analog boards in units globally . With Emona (and I would imagine other distributors) we will be sent the new boards with some calibration software and instructions . I don't yet know what is involved with the board replacement and calibration etc but most likely we will be performing the replacement at our service center . I'm also not sure of a timeframe due to the large logistics involved but at least it is very good news for all existing users of the DP power supply.
 

Offline Fsck

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #326 on: September 05, 2013, 05:19:55 am »
at least they have a solution, but god that's going to be painful logistics.
who pays for transport to and from?
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Offline Corporate666

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #327 on: September 05, 2013, 05:28:22 am »
UPDATE:

From John South at Emona:
Quote
Rigol will be replacing the Analog boards in units globally . With Emona (and I would imagine other distributors) we will be sent the new boards with some calibration software and instructions . I don't yet know what is involved with the board replacement and calibration etc but most likely we will be performing the replacement at our service center . I'm also not sure of a timeframe due to the large logistics involved but at least it is very good news for all existing users of the DP power supply.

Awesome, thanks for the follow-up Dave.

I am actually quite impressed with Rigol.

Every company makes mistakes.  Every company eventually ships something they wished they hadn't.  What separates the men from the boys is how they handle it.

As for shipping, I know people will complain about having to ship their units to Rigol, but nobody has a god-given right to not be inconvenienced in any way.  If my TV breaks, I don't expect Sony to cover the fuel cost to drive it to them or to compensate me for my time driving back to the store... as we say "shit happens".  Yeah, it's an inconvenience, but at least Rigol is taking care of it - reflects very well on them, IMO.
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Offline wizzy

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #328 on: September 05, 2013, 09:27:48 am »
I measured the heat sink temperature in my power supply. (Fluke 179 + k type thermocouple)

Ambient temp:                    22C
10min idle:                          44C
30min idle:                          44C
90min idle:                          46.5C

Idle is all channels on, no load, voltage 1:32v 2:32v 3:5.3v

I will update as the night goes on.

Mains voltage:                    244Vac
« Last Edit: September 05, 2013, 12:13:04 pm by wizzy »
 

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #329 on: September 05, 2013, 09:30:26 am »
10min idle:                          44C

Seems a bit low compared to what Rigol themselves measured.
Are you getting nice firm pressure on the heatsink?
 

Offline wizzy

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #330 on: September 05, 2013, 09:50:46 am »
I'm holding it firmly against the side of the heat sink, the one facing the vent. I have to hold it there for about a minute before it stops moving. Its possible the readings are being interfered with by airflow around the thermocouple.

I don't feel like taking the unit apart. It would be a difficult one to explain to the boss.
 

Offline Sparky

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #331 on: September 05, 2013, 10:09:49 am »
UPDATE:

From John South at Emona:
Quote
Rigol will be replacing the Analog boards in units globally . With Emona (and I would imagine other distributors) we will be sent the new boards with some calibration software and instructions . I don't yet know what is involved with the board replacement and calibration etc but most likely we will be performing the replacement at our service center . I'm also not sure of a timeframe due to the large logistics involved but at least it is very good news for all existing users of the DP power supply.

Aces, Rigol!  If you read this, a big THANKS for addressing this issue in a professional manner.  I have three Rigol products I'm really happy with --- I will easily buy more if this hardware fix pans out.

 

Offline madires

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #332 on: September 05, 2013, 10:54:36 am »
Zeitech are saying contact Rigol directly. EU law says they have to deal with it. Hmm.

I'll contact Rigol, see what they I suppose.

Since Zeittech is located in DE they have to obey the BGB (basic law about contracts). If the toy you just bought has a known defective you may ask the seller to get you a working unit, fix the problem or take it back and refund you. Some sellers try to intimidate buyers to contact the vendor for warranty to save money & time for honouring your BGB rights. In that case tell them that you know about the BGB and wouldn't hesitate to involve your lawyer. But if you bought the unit for a/your company it's a little bit different, but the seller is still accountable for that he sold you a good unit.
 

Offline marmad

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #333 on: September 05, 2013, 10:59:50 am »
Seems a bit low compared to what Rigol themselves measured.
Are you getting nice firm pressure on the heatsink?

Perhaps Rigol's measurements were with the board outside of the case, as in your video?

When I saw the photo of the new heatsink, I also thought it should be bigger - but maybe once Rigol discovered the initial mistake, they actually figured out the optimum size for a balance between heat transfer and good airflow in the case.
 

Offline Omicron

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #334 on: September 05, 2013, 11:10:34 am »
I measured the heat sink temperature in my power supply. (Fluke 179 + k type thermocouple)

Ambient temp:                    22C
10min idle:                          44C
30min idle:                          44C
90min idle:                          46.5C

Idle is all channels on, no load, voltage 1:32v 2:32v 3:5.3v

I will update as the night goes on.

I received a DP832A earlier this week from Batronix in Germany. It has the revised PCB in it. I measure very similar temperatures, also using a thermocouple pressed against the heat sink through the ventilation holes. I waited until the temperature didn't seem to rise anymore and got something around 47 C.
 

Offline HackedFridgeMagnet

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #335 on: September 05, 2013, 11:41:26 am »
The other obvious thing to measure is the supply voltage.
This would also have a significant effect if it was near the peak of it's allowable range.
In Australia it is 230V + 10% or -6% = 253Vac - 216Vac.

If for example at 230vac the voltage rectifies to 12Vdc on load which causes a voltage drop of 7volts and power loss of 4.9 watts at 700mA.
Then at 253vac the voltage would rectify to 13.2Vdc on load which causes a voltage drop of 8.2volts and power loss of 5.74 watts at 700mA.
Which is an increase of 17% power over an already stressed system.

I recommend any heat measurements also have maybe ambient temp and supply voltage too.


 

Offline wizzy

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #336 on: September 05, 2013, 12:14:56 pm »
I recommend any heat measurements also have maybe ambient temp and supply voltage too.

I've updated my post but it was 244Vac.
 

studio25

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #337 on: September 05, 2013, 01:06:20 pm »
 

Offline BravoV

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #338 on: September 05, 2013, 01:24:59 pm »
KeyGen for dp832 available.

https://www.eevblog.com/forum/testgear/sniffing-the-rigol%27s-internal-i2c-bus/msg287042/#msg287042
Looking at the timing in this crowded and huge discussion thread, this particular post made me chuckle.  :-DD

Offline jzoeller

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #339 on: September 05, 2013, 01:55:54 pm »
I purchased the "A" model of this supply about a month ago. I can verify that I have the model with the revised board. I'm in Cincinnati Ohio, USA.

Jesse
Jesse Zoeller
Computer Engineer
 

Offline lemon

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #340 on: September 05, 2013, 02:39:13 pm »
Do you know from what serial number done this new board revision?

That is unknown at this stage.
Should be visible through the vent holes though.

For those asking for the serial number: DP8C1532014XX

@ wizzy = this is the serial number that from this and after they fixed the issue?

Today I received the DP-832 that I have ordered before one month.

I can't break the warranty tape to see inside and I can't to see well inside via the side holes because it was afternoon.

I worked with this without any load for an hour and push the sense of temprature from the side holes. I write maximum temperature 65°C with ambient 27-28°C.
For the next two hours with loads and no loads the temprature was 58-65°C.
The serial number is DP8C1533014XX.
Before I receive the psu, ask from Owon Dealer to my country to confirm me that this psu hasn't this issue. They contacted with Owon Service Depatrment in Germany and the answers that gave them was "We have fixed that problem and your mentioned product has not that problem".

Tomorrow with the light of day, I'll try to see better via the holes and perhaps take a good photo from this area of board.

Update
I looked via the holes and  I can verify that I have the model with the revised board.
It has DP8C1533014XX serial number, digital version 00.01.06 and Cal Time 2013-8-17.

With the probe cable sense (not very accurate like Fluke) measures via holes, after 80 minutes temperatures btw 47-68°C according to heatshink point (look at the attachment photo). Of course the case was closed and the ambient temperature was 27-28°C.
« Last Edit: September 05, 2013, 02:53:32 pm by lemon »
 

Offline DarkPrince

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #341 on: September 05, 2013, 02:59:20 pm »
Good to see things turning around for the Rigol PSU. Though also unfortunate to me because now I have that itch to acquire one. Something to accompany my Mastech power supply which is a pain to dail to within 100mV possibly? I'll have to ponder thee.
 

Offline Bored@Work

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #342 on: September 05, 2013, 05:04:51 pm »
Zeitech are saying contact Rigol directly. EU law says they have to deal with it. Hmm.

I'll contact Rigol, see what they I suppose.

If you are in the EU, find your local (not the German, unless you are in Germany)  ECC http://ec.europa.eu/consumers/ecc/index_en.htm Contact them, tell them you have an issue with a retailer in another EU country and ask them for their advice.
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Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #343 on: September 05, 2013, 06:04:37 pm »
With my main at 207V (I know, it's low!), I've recorded 67°C after 6 min. idle (all outputs on with no load).

Edit: "buggy" REV 2 board, agilent probe through holes with closed case, 25°C ambient temperature
« Last Edit: September 05, 2013, 08:28:19 pm by mcinque »
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshits
 

Offline wizzy

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #344 on: September 05, 2013, 08:16:39 pm »
With the probe cable sense (not very accurate like Fluke) measures via holes, after 80 minutes temperatures btw 47-68°C according to heatshink point (look at the attachment photo). Of course the case was closed and the ambient temperature was 27-28°C.

This is as I suspected. Would be nice to get temps directly on the regulator but far too difficult without pulling it apart.
 

studio25

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #345 on: September 05, 2013, 08:36:12 pm »
The password for the DP832 "ManualCal" menu is "2012".
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #346 on: September 05, 2013, 08:52:21 pm »
I suspect that the fix that Rigol has showed was not specifically planned for ours buggy DP832s.

I mean that it's NOT their quick reply to what Dave has discovered.

Since Rigol have recently released a couple of new models in China (811A 40V/5A?+ 20V/10A and 821A 60V/1A + 8V/10A) I bet that instead a quick response, the new REV3 corrections for the DP800 series was originally implemented for that new models.

Now that they have no excuses about bad design, they are replacing the buggy boards with the new production.

It doesn't change the fact that we could have a fix, but it sounds different to me than "a quick response to an issue".



« Last Edit: September 05, 2013, 08:54:00 pm by mcinque »
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshits
 

Offline nack

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #347 on: September 05, 2013, 08:59:37 pm »
Dave never stated that the PCB fix was a response to his findings.
 

Offline mcinque

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #348 on: September 05, 2013, 09:06:02 pm »
Dave never stated that the PCB fix was a response to his findings.

Neither me.

I was criticizing Rigol, not Dave.

It was only my feeling reading some congratulations posts to the DP832's fix.

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

Offline hikariuk

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Re: EEVblog #512 - Rigol DP832 Bad Design Investigation
« Reply #349 on: September 06, 2013, 07:51:15 am »
Is the only difference between the DP832 and the DP832A simply that the A has all the features enabled and that it has a multi colour display, instead of mono coloured display (despite, I suspect, being the same TFT).

I'm Tempted to buy once the dust has settled and the chances of it needing immediate warranty attention have reduced.  On a related note, where do people tend to snag Rigol kit from in the UK?

I write software.  I'd far rather be doing something else.
 


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