EEVblog #549 - Rigol DP832 Lab Power Supply Followup

[alm]

Note that you either need one terminated in banana jacks or a type K to banana jack adapter to use the 187's built-in temperature function.

[olsenn]

I contacted Rigol about getting the new top board replaced, but they insist I have to send in my full DP832 for them to fix it, and they won't just send me a new board like they did for Dave. What a bummer -- it's not worth all the shipping and customs fees, plus waiting to get my PSU back.

Has the overheating issue bricked anyone's DP832 yet? It it's only left on for an hour or two at a time, is it likely that the board will fail in short time (I'm in North America if that makes a difference)? Would fixing it be as simple as putting a new 317 in (or will it break down the caps and surrounding circuitry as well)?

[jrgandara]

Thank you guys for all info!

The Insteak PS looks nice, but no separated on/off switches is a no no for me. I liked a lot the features and interface of the Rigol 832, but it is damn deep! I still think if I can manage to live with this size, but for now I will wait.

Some time ago I made a product and the heat of the 7805 is way too much to low 12V to 5V. So I replaced with a LM2575-5. This IC is over 90% of efficiency and worked cool. Why Rigol prefer heat in a lab PS?

[Zbig]

I´m looking for a new PS for my bench and, in general, I liked this DP832. Obviously those circular keys are ridiculous, but the features and the display looks very nice. But 42 cm deep is too much for my bench. Why so deep?

Two questions:

Any other option with similar features and maximum 32cm deep?
[..]

At the risk of sounding like a broken record (or scratched CD, for all the youngsters), yes, there actually is. It's called Siglent SPD3303D or SPD3303S, and it's about 30 cm deep. And no, contrary to the popular belief, I don't work for them

[Rigby]

That is a 2 edged sword, what about full current transient response without the output cap?  Some old hp supplies have the output cap connected thru rear terminal straps so you can unstrap the cap when you don't want it.

The rear strapping configuration of those old HPs is possibly their most under-used and under-rated feature.  The ability to slave supplies and configure them this way is excellent, IMHO.

[tailwheel]

I've newly acquired a DP832A power supply. After watching Daves video, I was curious about the rampup time on the voltage with current limit set low.

Doing what Dave did - set voltage to 32V and current to 1mA, I compared CH1 and CH2 ramp up times from 0V to 32V...
CH1 takes < 5 seconds
CH2 takes 17 seconds

The 17 second time seems to agree with what I was seeing in the video.
The large discrepancy in ramp up times between CH1 and CH2 doesn't seem right to me.

Coincidentally, I am also unable to calibrate CH1 VADC (output voltage reading) to be within the ballpark of spec. Although I was foolish enough to try the calibration using a Fluke 87V, I am able to get the calibration on CH2 to within at least a few hundred mV. Of course, this is still well out of spec., and I guess expected given I'm dong the cal with my 87V, but the difference in the results between CH1 and CH2 is concerning.

So to my eyes, there seems to be an issue with CH1 on this power supply.
Any thoughts on this from anyone? Much appreciated.

[Rigby]

why are you calibrating a new supply?  don't dink with calibration unless you know what you are doing and you have the proper equipment.   

somewhere I believe there are calibration instructions for the dp832. if you don't have them, find them, and if you can get an inexpensive voltage standard on eBay (they can be had) you might be able to make something happen with it, such as finding out how far your 87V is out.

[tailwheel]

why are you calibrating a new supply?  don't dink with calibration unless you know what you are doing and you have the proper equipment.   

somewhere I believe there are calibration instructions for the dp832. if you don't have them, find them, and if you can get an inexpensive voltage standard on eBay (they can be had) you might be able to make something happen with it, such as finding out how far your 87V is out.

Well, yes, lesson learned. CH1 seemed slightly out of cal so I tried. I do have the documentation on calibration procedure and I willfully ignored the recommendation to use a 6 1/2 digit DMM.
But the calibration is really beside the point of my post. I am concerned about the difference btwn CH1 and CH2 regarding the ramp up test I described. Seems concerning.

[Rigby]

try ch3, too.

I'm wondering if ch2 and ch3 being common has anything to do with it.

besides, if your calibration is out, you can't really trust anything about it until it is calibrated again.  it might think it is sending 1ma into ch1 but actually be sending 3ma.  if cal is out, you cannot trust those times.

[tailwheel]

try ch3, too.
besides, if your calibration is out, you can't really trust anything about it until it is calibrated again.  it might think it is sending 1ma into ch1 but actually be sending 3ma.  if cal is out, you cannot trust those times.

followup... First, I'm not very smart , and second, you are correct, current limit on ch1 is off by 2-3 ma. I set the limit to 1mA, it actually limits to 3-4ma.  I suppose that's within the spec for that. Don't know if it has anything to do with what I did. Thanks for the feedback.

[stormbr]

Hi all,

Sorry for repeat my problem, but i lost two channels (2 and 3) of my dp832, after that i install the new top board (version 2.01).

I  can calibrate just the channel 1 and him works fine, i have sure that follow all steps recommended by rigol correctly.

I updated  the firmware and bootloader of version 1.03 to 1.09.

Somebody have any idea to help me solve this problem ?

Thanks.

[ted572]

Hi all,

Sorry for repeat my problem, but i lost two channels (2 and 3) of my dp832, after that i install the new top board (version 2.01).

I  can calibrate just the channel 1 and him works fine, i have sure that follow all steps recommended by rigol correctly.

I updated  the firmware and bootloader of version 1.03 to 1.09.

Somebody have any idea to help me solve this problem ?

Thanks.

Have you seen the new Rigol 2014 Calibration Guide attached here?

[T2]

For those observing intermittent reboots of their RIGOL DP832 (as Dave has observed as well), check this thread:
https://www.eevblog.com/forum/testgear/rigol-dp832-random-reboots/25/

It may be related indirectly to overheating the regulator (probably increases the chance to trigger it), but IMHO it's simply bad/wrong design of the digital power supply circuitry of the embedded controller.

@EEVBlog: might be something to look into? 

/Thomas