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half-dead UPS

Discussion in 'Troubleshooting and Repair' started by bam, Oct 4, 2011.

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  1. bam

    bam

    6
    0
    Oct 4, 2011
    Hello,

    So, I got this UPS that stopped working on the battery powered side. There are 3 outlets on the battery side and 3 other outlets that are normal, non battery supplied.

    So I have a relatively small amount of electronic knowledge, so opened the thing up to look for something simple... hmmm.

    So I found something! When the UPS is under tension, there is a relay that should be powered up to get the power up to the battery supplied outlets, this relay doesn't get activated.

    It is a 12v dc N/O relay, I tried it and it works when I put 12v dc to it's coil and I get continuity from the wall prong to the battery supplied outlets when the relay is activated, so something between the power cord and the relay's coil is wrong, but what?

    I here post a few pics to make this a bit clearer. (sorry for my cheapo cam)

    1-the resetable fuse at the beginning of the circuit, I get no resistance so I guess it's ok
    [​IMG]

    2-power comes through the 2 bottom clips and I can follow it up to the 2 upper clips. See next pic to see the other side of the board)
    [​IMG]

    3-these 2 resistors are the + and - power lines, from here, they split in many directions, so I don't know how to follow the circuit from here.
    [​IMG]

    4- the 2 clips are connected to the coil of the relay. The pencil shows 1 of the 2 pins of a contact, the other pin of that same contact is above it. There are 3 contacts (one for each outlet) the 2 other ones are right beside the first one, on its right side.
    [​IMG]

    5- the pencil point to the relay that stays mute.
    [​IMG]

    If anybody thinks it would be possible to guide me through some sort of troubleshooting, I would greatly appreciate to learn how to see through these always breaking things!

    thanks

    P
     
  2. TBennettcc

    TBennettcc

    292
    2
    Dec 4, 2010
    Is there any way you can follow the circuit from AC-IN until the relay? (Unless you're telling me in picture 3 that those resistors are actually the AC line and neutral connections, and not + and - (which would indicate DC voltage from the battery...))

    What do you mean by "When the UPS is under tension"? Are you trying to say when you have the UPS plugged into mains AC?

    When the UPS is plugged into the mains AC, do you get voltage on the 3 "surge-only" outlets?

    Make sure the power is off, and check the continuity of all inductors, chokes, and transformers.
     
  3. bam

    bam

    6
    0
    Oct 4, 2011
    Oups, you're right, sorry about that, these 2 resistors are the end of the AC trail for me, they give +/- 18v AC each, (if I measure them individualy with one probe on the gnd and one probe on the resistor)

    Yes, that was my intention. Wrong dialect...

    yes I do, but the unit is not powered on, normally, I plug it into the wall socket and press the power button for 3 seconds, then I hear the click of the relay and a long beep, and then I depress the button and up it goes. But now, I press the button and nothing, absolutely no sound no leds no nothing. But I still got power on the 3 «surge-only» outlets, which is normal.

    As for the parts you're telling me to check for continuity, I'm trying to sort them out, here's what I found so far:
    1 transfo which seems to have 9 pins welded on the pcb, it's hard to tell though. I numbered them T1 to T9 on picture #2
    then
    3 inductors/chockes (I can't make the difference between them, research pending...)

    pic#1
    [​IMG]
    pic#2
    [​IMG]

    I would need help(or time) to sort out the coils and their pins. Mostly, I'm not sure what I'm looking for, I guess I need to have continuity to check if the coils are ok.

    So, on the transfo, i get continuity between all pins from T1 through T6, then also from T7 through T9, and between the 2 series there is nothing and no resistance (or should I say infinite resistance?)

    On the inductor #1
    continuity between
    i1b & i1e & i1f (i1f has no weld)
    and between
    i1a & i1c & i1d

    On the inductor #2
    continuity between
    i2a & i2b


    On the inductor #3
    continuity between
    i3c & i3d and nothing else! there are 5 diodes(?) dead right under that inductor thoughn so there might be something to look at over there.)

    So, this is where I'm at now, I'll try to look for datasheet for these parts because I'm not sure what to do with that info,

    thanks
     
  4. TBennettcc

    TBennettcc

    292
    2
    Dec 4, 2010
    What you have labelled as inductors/chokes 1 and 3 are probably transformers. Number two is likely an inductor/choke (same thing, really).

    Typically, a transformer that is not center-tapped will have one primary winding and one secondary winding. These are basically two inductor coils placed right next to each other. Each pair should have continuity, and each pair should be separate from the other.

    Why do you think you have five dead diodes? What makes you think they are dead, or even diodes for that matter?
     
  5. bam

    bam

    6
    0
    Oct 4, 2011

    what I meant by
    was just right under, I wrote dead right under to emphasize the fact that the diodes where probably linked to the device, wrong wording I guess, especially when trying to sort out parts that might actually really be dead...

    As for why I think they are diodes; there is a D infront of their ID number as there is an R in front of resistors, those I can tell because I can recognize them physically, so, since I have sometimes seen diodes that looked like these D'd things, I just guessed that they probably where diodes, but I might be wrong.
     
  6. TBennettcc

    TBennettcc

    292
    2
    Dec 4, 2010
    T1 and T2 are connected, T3 and T4 are connected, and T5 and T6 are connected. They are each connected by the traces on the bottom of the board. There wouldn't be a point of making a coil in the transformer only to short it out at the bottom of the board. A more likely scenario could be that T7 and T8 are the primary, with (T1 and T2) and (T5 and T6) as the secondary, center-tapped at (T3 and T4). Why they would two wires, I'm not sure.

    After looking closely at your pictures, I believe you have the pins of (what you labelled) the transformer and the first inductor identified incorrectly. It's hard for me to tell, because I don't have the board physically in front of me, but I tried to line up the components to see what fit.

    Try again.
     
  7. bam

    bam

    6
    0
    Oct 4, 2011
    I looked carefuly and I don't think there was any incorrect ID, to be sure, I measured the location of each part and then traced it on the other side of the board. I have posted very large pictures of both sides of the board to make it possible to compare. I also flipped the partside picture to put them in the same orientation.

    partside, unflipped
    [​IMG]

    partside, flipped
    [​IMG]

    circuitside
    [​IMG][/IMG]

    as for the continuities its the same,

    on the «big» transfo,
    can't find any google info with the part numbers on the items.
    big transfo is:
    080-49086-00
    E210832 SBI 4.2

    continuity between pins:
    T1 to T6 then T7 to T9

    then on the smaller one beside it on its left
    080-49071-00
    E140166 XPB-5 0539 (there are notes about XPB-5 transfos being class 130, don't know if that helps)

    continuity between pins:
    i1e & i1b (& i1f which is not soldered (unused center tap?))
    i1a & i1c & i1d

    then the inductor
    082-00055-00 LC
    LION 0547
    DASH 2 B-5

    continuity between pins:
    12a & 12b


    and the last smaller transfo
    080-20503-02
    DASH 2 B-5 (found «CLASS 130(B) INSULATION SYSTEM»)

    continuity between pins:
    i3c & i3d
    i3a & 13b, no continuity but a resistance of 69 ohm...

    If I could be oriented in a direction, I would be a little less lost.

    thanks
     
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