Trouble with Daker DK 3000 UPS

[CidiRome]

Hi.

I'm turning my head around a Daker (Legrand) DK 3000 UPS.

This is an online double conversion UPS that seems quite good.

When powered on the "!" led lits and there is no power on the output sockets.

With the software, the error I get is "no output" (can't remember the exact words, but that is what the error means).

While testing I noticed that the BUS voltages (positive and negative) go up for a moment to about 450V each (close to 1kV between BUS- and BUS+ that sometimes the Multi-meter overloads) and then start falling down slowly (CAPS discharging).

I couldn't found any short circuits and the Big Relay never seems to close (I tested it offline and it make a big noise that would be very audible), nor the one small relay in the main board. From what I can tell only the output relays seems to switch, and those I was able to switch from the software.

It also doesn't have power output with a cold start from batteries.

Any ideas?

Cheers.

[kc8adu]

Re: Trouble with Daker DK 3000 UPS

need pics.
also verify batteries are ok and charged.
many ups wont work at all with dead or bad batteries.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

I will add pics on Monday.

The batteries were replaced a few months ago and I also believe that this UPS is able to start without them.

Normally I'm making tests without the batteries connected and it notifies the situation through the battery error led that doesn't lit when the batteries are connected.

Cheers.

[Longbow]

Re: Trouble with Daker DK 3000 UPS

They don't work without the batteries, contrary to all internet rumors.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

About the Startup without batteries or with bad batteries, I'm pretty sure this one does: this is not a kick low price UPS, it is on-line. I agree you for off-line and line interactive UPS, if fact I know that most of those wont start without or with dead batteries.

I'm sending pictures of it, any ideas?

Cheers.

[Longbow]

Re: Trouble with Daker DK 3000 UPS

Ouch! That diagnostic software really works. "No output." Any chance to locate some schematics?

[kc8adu]

Re: Trouble with Daker DK 3000 UPS

start by load testing each battery.
one looks bulged.
a simple cheese grater tester is fine.

[budm]

Re: Trouble with Daker DK 3000 UPS

It does not look anything like this one:

Heatsink looks too small to be for 3000VA.
https://www.badcaps.net/forum/attach...4&d=1486979341
Did you check all the fuses the main supplies board.
There are at least 4 fuses.
What are the Voltage rating of the caps that you read +/-450VDC on? Booster circuit must be working at least to get Voltage that high. to get 230V RMS, the peak to peak out has to be around 650V P-P.

[CapLeaker]

Re: Trouble with Daker DK 3000 UPS

I am curious too on what you get on the main filter caps. Sounds like it wants to turn on but it can't, so it shuts down again. If the PFC isn't working, nothing will come out on the other end. This is a online ups, so the power will be conditioned all the the time.
I have online ups's that wont go without batteries. So make sure the batteries have juice.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

In replay to kc8adu:
- I inspected each battery and none is bulged, anyway I will test each one in another smaller UPS with some load.

In replay to budm:
- The one it that PDF it is very similar, that seems to be a newer model/design, I bet that the insides are mostly the same.
- About the heat sink, I don't fully understand this UPS (obviously), but the heat sink in the picture you referred is not the biggest, the other one that has the FETs on the other side is bigger.
- I checked all the fuses I could find (At least 8, and none is blown);
- There is a bridge of wires (blue/red/black) between the two boards labelled (GND/BUS+/BUS-) where I measured at least +450 and -450 to the GND, the multimeter overloads when measuring BUS- to BUS+. The caps are ratted 450WV/470uF.

In reply to CapLeaker:
- Yep, that is what I think about it wanting to turn on and something not letting. About it working without batteries, I think that I've seen it working without batteries when it was here to replace them, but it was a few months ago and I'm not 100% sure.

I hope my input can help you helping me.

Cheers.

[CapLeaker]

Re: Trouble with Daker DK 3000 UPS

Did you check the DC voltage on the main filter capacitors to see if the PFC turns on or not?

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

If I can remember correctly the DC power goes from the left board (smaller) to the right one but I don't understand the exact functionality.

Where should I measure the main filter caps, where are those?
How do I check if the PFC turns on?

It seems that the SG3525 is not generating the signals to the FETS but I don't know if this is caused by itself or if it is not "instructed" to start. I replaced it with one from a scrap UPS that I had around but it may also be bad. I'm waiting for new ones to arrive.

Sorry for the beginner questions...

Cheers.

[budm]

Re: Trouble with Daker DK 3000 UPS

"- There is a bridge of wires (blue/red/black) between the two boards labelled (GND/BUS+/BUS-) where I measured at least +450 and -450 to the GND, the multimeter overloads when measuring BUS- to BUS+. The caps are ratted 450WV/470u"
That cannot be right to have 450VDC on the 450VDC, there is really no head room at all.
Are you sure your meter is OK?
BTW, is there bypass switch to get the AC at the AC outlets of the UPS?

[Behemot]

Re: Trouble with Daker DK 3000 UPS

Isn't possible the voltage are floating against earth ground and he measured against ground, so found higher ones?

[CapLeaker]

Re: Trouble with Daker DK 3000 UPS

Your Line Voltage is 230V x 1.414 = 325V That is rectified LV without the booster circuit. When the PFC (booster) is working you should see some 400V there, but not 450V on a 450V cap. That high measurement is either user error, battery is bad in your meter, or the meter is bad. You have to use both probes on the main filter capacitor. For everything you measure in the primary section, the negative post of the main filter capacitor is your reference GND point.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

As stated, if that floats above ground voltage, you can measure much more. Not all SMPSes are ground-referenced, especially on the primary side! I actually learned my lesson with some of the cheap UPSes, when there was about 100 V between battery - and earth ground

And even some which do look like there is earth potential, like APC Back-UPS RS series, there are fact some PN junctions between them which you short if you ground the batt -

[Longbow]

Re: Trouble with Daker DK 3000 UPS

It would be great to have at least an owner's manual for this unit. Is there a microprocessor in this unit - it might be involved in startup. You should email the factory and ask for a service manual. The worst they can say is no.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

OFC there is microprocessor, always.

[Longbow]

Re: Trouble with Daker DK 3000 UPS

Well, here is the OM. At least there are a few comments about how to operate the front panel controls. My thought was to make sure that the micro was not keeping the unit from powering up and perhaps needs a hard reset?

Also, there might be a super cap or small coin battery for user parameter storage that is failing. Also important are details about the history of operation - such as how long was the unit in service, did it fail during a power surge, did it fail during a UPS event, and so forth.



Operation via front panel is shown here. This would make me crazy. Perhaps the software is the best way to access the features.
https://www.youtube.com/watch?v=ErZHfoDHNZg

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

I've compiled a pack of pictures of this ups with more quality, it can be downloaded from http://vieirasoft.net/DK3000_Pictures.zip

Meanwhile I've tested each battery and they were all able to cold start an UPS with computer hooked on it and work for a few minutes.

The YouTube Video is not related to this UPS and curiously I had seen it before...

Couldn't find any coin type battery, how the a super cap looks like?

I've been using this multi-meter for a few years, it is not a top of the line one, but has always done the job.

I think this UPS should have an internal bypass, but if it has I've never seen it working nor I know how to activate it.

Cheers.