Author Topic: NEW DP832 - 33V !!! voltage when powering on... (Read 5987 times)

alank2 · « **on:** June 28, 2020, 12:44:28 am »

I got this yesterday. CH1 is outputting a voltage as soon as I flip the switch while the rigol logo comes up. It was connected to a 5V project and I think it was outputting 6V, then 7V. I disconnected it and connecting a meter it outputs 33V at power on. Any thoughts? I can try to reflash the latest firmware. My other DP832 does not do this.

Updated firmware/analog board update. no change. During power up channel 1 goes to 33V for a few seconds...

maginnovision · « **Reply #1 on:** June 28, 2020, 01:21:24 am »

Work around it by not having anything connected or initiate a return/replacement.

alank2 · « **Reply #2 on:** June 28, 2020, 01:45:25 am »

Yep, CH2/CH3 do not do it, but I'll be calling for a replacement. I just wondered if anyone else has seen this fault before.

alank2 · « **Reply #3 on:** June 28, 2020, 01:51:29 am »

For kicks I wanted to see what it would deliver - I put a 25W 25ohm load on it and this brought the 33V down to 1.95V with 80mA delivered across the load during power on. I'll get a replacement.

Jan Audio · « **Reply #4 on:** June 28, 2020, 04:27:55 pm »

Glad i did not buy this garbage, they did advice me to buy it.

2N3055 · « **Reply #5 on:** June 28, 2020, 04:41:07 pm »

Quote from: Jan Audio on June 28, 2020, 04:27:55 pm

Glad i did not buy this garbage, they did advice me to buy it.

Don't be an ass.. there are thousands of these out there that work just fine. He got broken one. It happens.

It's not like when they made a PSU that on powerup destroyed 1500 USD development system, and after investigation it was discovered it was like that by design and they had to create new version of PSU with different suffix to fix it and recall old ones...
No wait, that wasn't Rigol, it was Keysight...

alank2 · « **Reply #6 on:** June 28, 2020, 05:10:29 pm »

Good find PeDre - that is the exact issue I am having on CHA (presumably power board 1). It would be nice to figure out what the fault is so someone could fix it themselves if their unit is out of warranty, but maybe it is a defect that it either comes with or doesn't - hopefully.

I really do love the DP832, this is my second one and my first one is 4 years old. I'll contact tequipment on Monday to get a replacement.

sequoia · « **Reply #7 on:** July 01, 2020, 12:36:53 am »

I just got a DP832 (also from tequipment), so first thing was to test if it has this issue.... Luckily my unit doesn't have this problem.

Factory calibration date appears to be from late April, so unit was manufactured relatively recently.

alank2 · « **Reply #8 on:** July 01, 2020, 12:39:58 am »

Thanks for the report -tequipment shipped me a replacement and it should be here Friday. I know the first thing I'm going to test as well!

Jan Audio · « **Reply #9 on:** July 01, 2020, 01:32:58 pm »

Quote from: 2N3055 on June 28, 2020, 04:41:07 pm

Don't be an ass.. there are thousands of these out there that work just fine. He got broken one. It happens.

Happens alot in china.

Gandalf_Sr · « **Reply #10 on:** July 02, 2020, 04:10:14 pm »

For one extra data point, I bought a new DP832 from TEquipment.net about a month ago; I just tested it and it doesn't have any voltage surge on Ch1 during power up.

alank2 · « **Reply #11 on:** July 02, 2020, 06:18:18 pm »

I'd check all three channels at power up to make sure! My replacement is coming tomorrow, that is the first thing I plan to test!

sequoia · « **Reply #12 on:** July 03, 2020, 05:32:42 am »

I hooked up all channels to a scope and this is what I see, when powering on the DP832:

NEW DP832 - 33V !!! voltage when powering on...

Gandalf_Sr · « **Reply #13 on:** July 03, 2020, 02:24:17 pm »

I just re-ran the test. I do get a 250 mS period of 3V on Ch1 on about 2 out of 3 power ups. Are you sure that you haven't got a x1 vs x10 setting error when you say it's 33V?

This should not be happening but it's not a big enough deal for me to return the DP832.

aristarchus · « **Reply #14 on:** July 03, 2020, 02:57:58 pm »

Has anyone else got data on what other similarly priced PSUs do upon powerup?
Eg Siglent, GWInstek, Tenma, B&K etc

Never tested that since I always have the PSU disconnected and connecting it only to perform specific tasks.
Having said that, I do like my DP832 as it has proven reliable and doing its job for 3 years now.

tom66 · « **Reply #15 on:** July 03, 2020, 04:03:52 pm »

IMO anything other than switch arcing and 100mV DC is unacceptable on a PSU when it turns on. My GW Instek PSP-603 has a relay isolator so no glitch happens at all when powered on. My EA-PS 2042-10B is similar, output no higher than 100mV when turning on.

There are many applications where you might have a sensitive component attached to your PSU. When the output or PSU is off, the output should be zero.

PeteH · « **Reply #16 on:** July 03, 2020, 04:12:13 pm »

I've seen this happen on a GW GPS4303 when you click off the physical power switch... Kicks the output...I think it's only with a certain series/parallel config (internally, with the buttons on the front of the unit)

NoisyBoy · « **Reply #17 on:** July 03, 2020, 06:12:59 pm »

I tried it on a few Agilent bench and system supplies at my hobby lab:

E3615A, there is no output off, so I have to set the output to zero and turn the unit on:
Unit 1: 0 spike at power on, I had to turn up the voltage just to make sure everything is connected properly.
Unit 2: Same as unit 1
Unit 3: It got a 20mV spike that smoothly ramp down to 0 after 300ms

6632A System Supply, it default to output on, but also default at 0V:
0 spike at power on.

6643A System Supply, it defaults to output off at power on:
Unit 1: 0 spike at power on.
Unit 2: 0 spike at power on.

E3631A bench supply, it defaults to output off at power on at all 3 outputs:
6V output: There is a -280mV voltage that lasted for 550ms
+25V output: 0 spike
-25V output: There is a 330mV voltage that lasted for 580ms

I expected the system supplies to be at a much higher standard than the bench supply, so their results is what I expected. The E3615A are my go to supplies for bench work, those are rock solid and the results bear that belief. I did learned something for the E3631A, I definitely will not leave it attached to sensitive DUTs while powering it up.

Back to the Rigol, I have to think the turn-on spike is excessive, you have to be careful not to leave delicate DUTs attached to it during power up.

JxR · « **Reply #18 on:** July 03, 2020, 08:18:23 pm »

Quote from: NoisyBoy on July 03, 2020, 06:12:59 pm

Back to the Rigol, I have to think the turn-on spike is excessive, you have to be careful not to leave delicate DUTs attached to it during power up.

In certain situations not even this is adequate. For instance, if you had a quick power interruption for your entire premise. I had almost an entire year in which additional housing was being built around my location. So quick power interruptions were regularly occurring. If I was in the middle of powering a circuit, it would then receive this input spike every time the power was momentarily interrupted. I ended up having to get rid of the DP832 solely due to this issue.

alank2 · « **Reply #19 on:** July 04, 2020, 12:02:04 am »

Replacement DP832 came in today - sadly CH1 outputs 24V when powering on.

I have 3 Fluke meters connected to each of the channel outputs.

Everyone should be checking their DP832 outputs when turning on - clearly Rigol has a batch of ones with an issue - this is two in a row for me.

thm_w · « **Reply #20 on:** July 04, 2020, 12:06:09 am »

Discussed here: https://www.eevblog.com/forum/testgear/is-rigol-dp832-output-voltage-spikes-when-unit-is-turned-on-an-real-problem/

Quote from: NoisyBoy on July 03, 2020, 06:12:59 pm

E3631A bench supply, it defaults to output off at power on at all 3 outputs:
6V output: There is a -280mV voltage that lasted for 550ms
+25V output: 0 spike
-25V output: There is a 330mV voltage that lasted for 580ms

I expected the system supplies to be at a much higher standard than the bench supply, so their results is what I expected. The E3615A are my go to supplies for bench work, those are rock solid and the results bear that belief. I did learned something for the E3631A, I definitely will not leave it attached to sensitive DUTs while powering it up.

I can't think of any part that would be damaged from 330mV? Maybe you are working on some cutting edge electronics.

edit: checked a DP832 here, on power on:
CH1 - 3V for 250ms
CH2 - -400mV
CH3 - -400mV

CH1 is concerning, the others are not.

DP832A:
CH1 - 1.5V

NoisyBoy · « **Reply #21 on:** July 04, 2020, 01:23:17 am »

thm_w, thanks. No, nothing ultra sensitive, just precautionary more than anything else, as I have not blown anything with any of these supplies.

I hope Rigol is able to correct the issue quickly, I hope those are just manufacturing defects and not caused by design updates, 25 and 33V spikes are very high for any bench supply.

sequoia · « **Reply #22 on:** July 04, 2020, 05:05:09 am »

Quote from: alank2 on July 04, 2020, 12:02:04 am

Replacement DP832 came in today - sadly CH1 outputs 24V when powering on.

I have 3 Fluke meters connected to each of the channel outputs.

Everyone should be checking their DP832 outputs when turning on - clearly Rigol has a batch of ones with an issue - this is two in a row for me.

That's pretty bad luck, or Rigol has a problem.... I guess I was lucky, since mine doesn't spike over 0.5V. Something to be aware off, but I don't think I'll return power supply for that. Did you check the (factory) calibration dates for your units?

Jan Audio · « **Reply #23 on:** July 04, 2020, 01:50:08 pm »

Now anyone still disagree with me ?
garbage

Gandalf_Sr · « **Reply #24 on:** July 04, 2020, 01:56:23 pm »

Quote from: Jan Audio on July 04, 2020, 01:50:08 pm

Now anyone still disagree with me ?
garbage

I disagree.


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Author Topic: NEW DP832 - 33V !!! voltage when powering on... (Read 5987 times)

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