APC Smart UPS 3000 XLM 2U, Suddenly dead, in bypass, no life at all, batteries fine.

[kssilence_apc]

This was originally posted on APC forums on 5/5/2015

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Hi Guys,

Just a bit earlier i had a circuit breaker (RCD / ELCB) trip in the house for one of the circuits which is a semi-frequent occurrence for reasons unknown yet (suspect leaky circuit or device, was happening before UPS was acquired), now I have a 3KVA APC Smart-UPS Modular (SUM3000RMXLI2U) in my room that is supposed to protect my desktop computer setup and until now always has protected it from outages, but this time the breaker tripped the UPS just went totally dead instantly and now won't turn on with the circuit reset. Unit was working fine right up until the breaker tripped, witnessed the trip and failure occur.

With the batteries connected, pressing the power on / test button results in a SINGLE click INSIDE the Inverter Module, No Fans, No Beeps and no lights AT ALL and the unit is otherwise TOTALLY unresponsive to the front panel. When the mains is plugged in with the battery connected you hear the usual loud "thunk" of the transformers being energized and the relay click with the load receiving power via Bypass but otherwise its exactly the same behaviour. When Plugged in the Unit DOES NOT supply charging voltage, and unplugging the battery pack results in the unit totally going dead after a few seconds with the bypass relay going open.

The battery pack has sufficient charge and reads above 52v, There is no burning smell, smoke, bangs, pops, arcing noises or anything else that would indicate a major internal failure of the High Voltage Inverter Module, the serial port is also totally unresponsive. I have removed the power module from the chassis and removed the top cover for a quick visual and smell inspection, but cant find anything obvious.

With the inverter module removed from the main chassis with the cover removed and the battery pack connected but unit not "turned on" I did a quick probe of the back of the Connector that goes from the "Brain board" to the Smart slot, Present was a "hot all the time" Battery voltage on one pin. With the unit attempted to be switched on (click occurs) the battery voltage is still present, but also present on another pin was 20-23v that was unstable. Battery current draw is this "turned on" state is unstable wildly bouncing between 50ma and 200ma (as fast as my DMM could update), when "off" it reads Zero as would be expected (No Smart slot card installed). 


Does anyone such as an APC engineer or technician have any suggestions as to what could have failed internally from the above information?
if required I can easily do more testing with a DMM and an Oscilloscope under direction as well as replace components if required (provided they can be sourced).
I have decent experience with electronics, and I am fully aware of the risks involved with high voltage and how to deal with them.

Thanks, Alex.

[BillP]

This reply was originally posted by Angela on APC forums on 5/6/2015

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This UPS is not user serviceable so I don't have any details available to me, nor are any of us employees that post here electrical engineers. If anyone else wants to post at their own risk regarding what to look at on the internals of the UPS, please feel free to do so!

If I was in this situation with what I know, I'd want to know if the Network Management Card (NMC) was still installed in the SmartSlot (that ships with this model of UPS) and if there were any lights on it. You mentioned checking the SmartSlot out a little bit internally so I was wondering if the NMC was in there and was energized when the UPS is plugged in to AC power. Even if the UPS doesn't start, sometimes the SmartSlot is powered.

[kssilence_apc]

This was originally posted on APC forums on 5/6/2015

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Hi Angela,
i thought that i did state before that there is no smart slot card in the slot of the suspect ups, when i got the UPS second hand first thing i did is i removed the card and installed it in the Smart UPS 2200XL that is protecting my Lab Rack equipment (that unit works perfectly fine), I dont exactly feel safe about putting the card back into this dead unit in case it fries the only network card that i have and that i need for my rack, anyway would the card even be able to provide any diagnostics when the serial port is dead because the unit doesnt respond?

i had a browse through the forums before and it seems that there have been a few cases where those who have knowledge on these units (UPS Designers, Techs, Others who have repaired a unit, etc) were able to PM or otherwise provide some help for owners to have a chance and fixing the unit themselves, and i would be very grateful if i could get some assistance on where to start troubleshooting despite the risks involved as i stated before, if it saves me a couple of grand i dont have in trying to get another unit, then im all for it.

Thanks, Alex

[BillP]

This reply was originally posted by Angela on APC forums on 5/6/2015

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Hi Alex,

I must have missed the no card installed part and I see it now - I apologize. I agree, if it wasn't already in there, it may be dangerous to add it to this UPS.

Can you give me the details on how you connected to the serial port and what you did there? The baud rate, cable used, etc? That way I can verify it was done properly to prove that the serial port is actually not responsive.

Yes, I agree, there may be some folks that can help you here at your own risks and that is fine but that person is not any of the employees that post here since we don't have that level of expertise. I just wanted to comment as an employee to clarify that we saw your post and won't have any answers but that other people can post. I also wanted to share what I actually did know regarding a situation like this.

People are free to post/assist you if they want/are able to.

[kssilence_apc · Accepted solution]

This was originally posted on APC forums on 5/6/2015

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Hi Angela,

For the serial port i grabbed the Official APC Smart Signalling cable, Connected it to a KNOWN working USB Serial dongle connected to my laptop and set the Port to 2400 8 N 1, Port totally unresponsive, Software tool "APCFIX" unable to communicate as well. Setup was verified working by connecting to the UPS in my rack and also the unit protecting the Router  in the study and interacting with the console, as well as using "APCFIX" which both work fine on the rack unit and the Study unit.

This same setup has previously worked just fine on this Suspect UPS. I also tried my Known working Self made smart signalling cable and as expected the result was the same.

If you want i could record a quick video clip on how the unit behaves when the battery is plugged it and unit attempted to be powered up, as well as having a DMM measuring battery voltage during the process, as well as repeating the attempt with mains connected?

- Alex.