APC Back-UPS NS 1250

[Uranium-235]

Given to me by a client. Little over a year old. Said I can have it. He said there is no voltage out the backup ports

Hooked up my multimeter I got voltage, unplugged it and it dropped to 0VAC.

Let it charge a little, unplugged it, suddenly got 172VAC

Opened it up, and it looks like smaller caps are a mix of TK, Jamicon and other crap. No burn/heat marks, has a big panasonic, and ONE weak spot...A single CapXon

Capxon's Ripple is 145 according to the DS. I found a nichicon on mouser with a ripple of about 245, close to the same size.

once I pick it up monday, I will give you the results

[Kiriakos GR]

Re: APC Back-UPS NS 1250

From what I see in this PCB board if some hand over an old robust UPS in those APC UPS exchange programs, he must be an idiot.

I own an APC SUA1000 XL which I got in 2004 and is indestructible.

[theokretes]

Re: APC Back-UPS NS 1250

Yes, APC uses cheap chinese capacitors in all of their products.

I'm surprised the primary is a Panasonic capacitor and not a festering TEAPO/G-Luxon.

[shovenose]

Re: APC Back-UPS NS 1250

Yeah my APC Back UPS RS 1500 is doing great It's pretty old but never had any problems.

[cheapie]

Re: APC Back-UPS NS 1250

Are those supposed to be heatsinks back there? They look more like heat storage devices of some sort.

[Uranium-235]

Re: APC Back-UPS NS 1250

I don't know what he did. I think cause it was over a year old he couldn't get it exchanged. (I think this particular one might of not had a good warranty)

they are big mosfet sinks

[cheapie]

Re: APC Back-UPS NS 1250

they are big mosfet sinks

It doesn't look like they'll dissipate much heat.

[Uranium-235]

Re: APC Back-UPS NS 1250

Maybe I spoke too soon. found this on the board. couldn't find the fucking camera so I had to take this with my laptop webcam

not sure its burnt glue or something worse

[y_not]

Re: APC Back-UPS NS 1250

From what I can tell of the pic, it looks like a component blew and those are its charred remains!
*says little prayer for poor departed component*

Can't tell what though, needs more light. Yeah, I know, couldn't find the camera. Hate it when things just ruuuun off! lol

[kc8adu]

Re: APC Back-UPS NS 1250

its glue on a hotspot.
replace at least the 2 caps near the 317.
those "heatsinks" are only good a few minutes.
these units are cheap junk.fix up and put on craigslist.sell.then buy an old metal one for next to nothing and run big external batteries on it.

[ben7]

Re: APC Back-UPS NS 1250

I think I recall there being another thread on here with a blown capXon, I think it was the smae model of UPS.

Yes that "burnt" component is not burnt, it is that yellow glue that turns dark brown from heat.

[Uranium-235]

Re: APC Back-UPS NS 1250

oh it wasn't a nichicon I ordered, but a UCC KXG. Still should be OK as the line isn't known for problems

I have it in, and working

I realized something...my DMM is busted, at least on AC, even reads the outlets as 174AC (house outlets)

its plugged in and charging. we'll see what happens

[Uranium-235]

Re: APC Back-UPS NS 1250

well...my meter had a BT indicator on it, and when it went off, the voltages started reading right

ether way, its no workie. It charges, and I can read it with my mm when I unplug it, but when I put it under any load it cuts off

[ben7]

Re: APC Back-UPS NS 1250

Make sure you aren't overloading it.

Have you checked the FETs, and checked to make sure the battery(s) are good? (I.E. not dropping voltage when the inverter kicks in)

Btw, cheap multimeters tend to loose accuracy as the battery drains ... LOL

[kc8adu]

Re: APC Back-UPS NS 1250

and make sure the battery isnt drooping under load.
the inverter may run ok with no load but the battery goes below the low voltage shutdown under load.
i use a car battery tester to check.plenty will sit at 12.9v and instantly drop to 0 when i turn on the load!

[Uranium-235]

Re: APC Back-UPS NS 1250

I used a dell dimension 3000...i'm pretty sure its not overloaded :P

...its a plug-in bench DMM

not quite sure how to check these fets

[Kiriakos GR]

Re: APC Back-UPS NS 1250

not quite sure how to check these fets

This is easy, there is only two types of them the dead and sorted or the good ones.

Before a week I tried to repair a UPS, one FET was blown from the four, but I did run out of luck.
The main IC control possessor was dead too.

[kc8adu]

Re: APC Back-UPS NS 1250

still sounds like a bad battery.
as for the fets in a ups there are the good and the blown to shit/burned up.

[smason]

Re: APC Back-UPS NS 1250

Interestingly, EEVBlog just did a teardown video of a SmartUPS 2200RM (considerably better quality than their cheaper ones)
I have one in a rack that gets nothing higher than 18 degree C air and the batteries last about 6 years, compared to room temperature units that go 2-3 years, and the one that lives under my desk at home which is in a warm spot averages 1.5 - 2 years between batteries.

[y_not]

Re: APC Back-UPS NS 1250

I only buy the higher end boost+trim models like the BR500/BR800 and they last for 7, sometimes 8 years before needing a battery change. They're awesome! Not a single problem with any of them, all over town and nearby cities @ client's businesses. I use the little one for network equipment and the larger for workstations.
I dot buy any of the models available through retail outlets, this stuff is distributor only, or direct channel sales.

You all are the experts and I'm only pointing this out so I can learn a bit more.
With that said, I still see what looks like charred remains between Q27 and D10. In fact, it even looks like there are 2 black holes just below Q27 and to either side, one of which is just above and to the right of the right most resistor lead.

I see the glue situation on that resistor and trickling down onto the board, it's all smoked and charred.
But the rest of that, is it really all glue? Why did they schlob it on there, what purpose did it serve in that spot? I know It's to keep components from vibrating, or to hold loose, non surface flush soldered through hole components in place. But here, I have no clue why they did it. Care to enlighten?

Also, why did this get so hot here?

As for fixing the unit, what's the trickle voltage like, have you tried swapping the batter(y)(ies) for known good suitable spares?