Trouble with Daker DK 3000 UPS

[Behemot]

Re: Trouble with Daker DK 3000 UPS

Supercaps are usually very wide and short, kinda like a button cell

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

Can't find any Cap that fits that description.

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

It would be just a very long shot, I've never met any UPS which would have volatile memory anyway. For the usual parameters even just a few kB of non-volatile memory built into the processor is more than enough.

[CapLeaker]

Re: Trouble with Daker DK 3000 UPS

Supercaps have a low voltage reading, like 2.7V or 5.5V and their capacity rating is usually in F (Farad), not uF etc.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

About this UPS, I have news: I was able to repair it (some bad component that was not entirely short, but was hard to detect).

But presently I have a second one of the same model that is not working correctly.

Based on the error code 14, the problem is "FAN ERROR", but all the fans are working correctly and I don't even know how it knows that a FAN is bad.

The fans are simple 2 PIN 12V fans with no rpm counter nor pwm controller.

It seems to be a controller board problem because while I had both UPS to test, this controller board did exactly the same with the other UPS that was otherwise working correctly.

Also: this one has a small vibration sound that come from somewhere close to the big relay. This sound is only present when the AC in connected.

Any Ideas?

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

What was that "some bad component"? State that you found it is useless for others when you don't say what it is.

I guess it looks what power draw there is from fans to detect their status?

[Longbow]

Re: Trouble with Daker DK 3000 UPS

Second. What was the mystery part, and how did you find it? By comparing it to a good one?

FAN ERROR would be detected either by current sensing, or by thermistor that indicates that the unit is too hot. But if heat were the trouble, you would think the error would say "OVERHEATING".

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

Sorry.

The bad component was a diode RHRP8120 (I found it by comparing the two units, but a close up checkup paying more attention would eventually find that bad diode).

About the fans, I also thought about that, but...

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

Yeah, I also blasted one in a different UPS once.

Maybe some small transistor went bad, there are often small SMD transistors around the fan headers, I guess to control the speed.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

If the small transistor have to be close from the fan header pins, then both UPS would have the same problem.

I was getting the fan error with both UPS but only with one controller board (pictures 20170220_182313.jpg and 20170220_182341.jpg in the zip file, this pictures are of the board that works correctly), the only difference between the boards is the firmware version.

Presently one of the fans is of a lower AMP rate and this also happened with a different fan of the other UPS. Can it be that the different firmware (newer) is being less sensitive to the fan consumption?

For the sake of the possibility, I will hook another fan in parallel to get an AMP rate closer from the original fan.

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

Oh not this crap again. It must be a Must Power or similar PoS, I've seen a few, the board was always baked, caps bad, similar with the stand-by/charger daughterboard. This one seems to at least have better layout but still, you are lucky it has not died yet.

Start with replacing ALL the capacitors on the board with something decent. Even if it is not the problem yet, it will be later. Actually you can replace all the smaller caps even on the main board.

[Longbow]

Re: Trouble with Daker DK 3000 UPS

Start with replacing ALL the capacitors on the board with something decent. Even if it is not the problem yet, it will be later. Actually you can replace all the smaller caps even on the main board.

Hah! Don't waste your money, if there is no hope of fixing it. Unless you get some schematics, or get very lucky finding a faulty part, consider it as a convenient source of spare parts.

There are lots of diodes in a unit like this. I assume that the one you found must be a large rectifier in the switching section. Even though parts fail for no good reason, I always assume that there is a good reason for failure. In other words, the main problem is waiting for you to fix it.

As far as your fan problem, it looks like you have several units with this error. In that case, the manufacturer would probably know exactly what is going on and may tell you how to fix it. Worth a try. If you have the time, carefully freezing individual parts in the fan circuit could help you locate the trouble.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

About the failed diode, that situation was was in the previous UPS, I replaced it and is working correctly.

In the second UPS:

- I'm still making tests, but, in the present UPS the FAN AMP rating seems to be important. I hooked another fan in parallel and it is now working.

- I mentioned before that this UPS has a vibration sound, it comes from somewhere in the red circle of the picture I'm attaching. What would be the most probable culprit component?

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

The PFC coils are making noises, that's quite normal.

I have had couple similar units in my hands, as stated, they are quite often a cheap Must Power (or something similar) crap. Dozens of different brands use the very same OEM, they are dying the same way after mostly the same time.

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

I'm not 100% sure this UPS is that kind of crap. This is an 3000VA Online UPS from a brand that presently is part of LeGrand.

I've seen plenty of that crap UPS (mostly mustek) that I don't even bother to repair when the issue is more than a dead battery.

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

There are dozens of brands using the same OEM (and even same platforms), this is clearly one of them. Last year at CeBIT I was disgusted by the scenery when 90 % of the brands there had the same UPS lines! I expect same or worse this year (in a few days actually).

This is reality man. You may think it is some brand but it is just another generic national brand which tries to get small share of european market. There are dozens such here, every now and than some firm tries to import them for a while, after few years everbody forgets it existed and it starts again. There are or have been just on our market brands from Spain, Hungary, Romania, Benelux, Germany etc. etc.

I still have 100 kilos worth transformers from these units. All 2200-3000 kVA on-line. And what, you think it's something special? There is a dozen of brands selling such units in any time even on such small market as czech is. I do not know half of them. But obviously they have to cut some corners when it costs 40-65 % less than Eaton, APC or some other decent brands.

[Longbow]

Re: Trouble with Daker DK 3000 UPS

Thanks for that observation Behemot. I guess it is not cost effective for hundreds of engineers to design their own version of a UPS. Since you mention that everyone uses the same design, it increases the chances that schematics can be obtained for those who wish to attempt a fix.

I suppose PFC coils can make noise, especially since they operate at the line frequency? - that makes sense. Also, ceramic capacitors are known to be noise makers since they are similar to piezoelectric speakers.

If it is necessary to use alternate fans, a modification could be done by increasing the value of the current sensing resistor. That part should be obvious because of its low resistance of around .1 ohm or less. Good luck.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

It decreases as it way to often means these brands have little to no knowledge, there are no engineers inside, they are basically just a reseller. Combined with crap OEM platform, you can imagine.

But who cares in the end? I am trying to promote refurbished APC Smart-UPS units here which are better than new in most ways and we even now cover them by three year warranty (plus option to buy up to 20 years), longer than official basic APC warranty. Or we can just refurbish customer's own.

Guess what: everybody continues to throw even still perfectly working HW away and buy new crappy one for incredible money every few years. (Yeah and employees do not get raise instead). This western civilisation is disgusting, everything is like toilet paper today, even cars - use couple times and throw away! This is going to be fun when current generation of cars will start dying before those fools can even pay their 10year loans on them…

[CidiRome]

Re: Trouble with Daker DK 3000 UPS

Hi.

Thanks for the information.

About this ups fan problem, even with the "two-fan-hack" I made for testing, it will only start-up about half of the times, the other half it will fail the start-up with error 14.

About the resistor you mentioned, is it possible that it would be located at the controller board? (remember that this controller board would give the same error in the other UPS that was working correctly with it's own controller board)

For my service, I have two APC Smart UPS and I like them very much.

A word about quality: some time ago I made a test with two basic UPS and the same battery. While the Mustek-crap-type worked about 15 minutes, the APC Back-UP UPS lasted about 40 minutes...

Cheers.

[Behemot]

Re: Trouble with Daker DK 3000 UPS

Of course, these cheap shits have aluminium transformer winding, among other things.