Symmetra XR 16KVA with a faulty MIM

[big_al_apc]

This was originally posted on APC forums on 9/29/2014

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Hello everyone,

I work for an IT company in Australia and basically do a swap and Go service on a Range of APC Symmetra UPS units.

A task is loged and I will go to site with the necessary Module test the unit and then swap the parts out as needed.

Yesterday I had a Old Symmetra XR 16KVA UPS  which had a failed Main Intelligence Module,

the unit was operating on its Redundant Module and the ups appeared to be healthy apart from the dead MIM.

But as I put it into Bypass , BANG ! and a bright spark came out of the MIM, even though it already had no LED lights on it.

That was a little bit off putting, but it did not appear to effect the UPS and the LCD  Display was reporting the unit was in Bypass and missing the MIM

it did  have the RED Fault LED on.

I removed the MIM  and as I did not have a replacement with me , I thought it would be safer not to reinsert this unit until I got a new replacement.

Now the problem that I had was as I put the unit out of Bypass it turned off the Load ! DOH !

Server, Workstations , Registers all went out , Double DOH .

I put it back in to Bypass and we started to get the site back online over the next 10 to 20 minutes.

So did it fail because I put it online without a MIM installed even though the RIM looked to be ok?

I wondered if the unit needs the MIM installed even if it is faulty as there maybe there some kind of switching the unit needs

or have people done that before without any issues?

I have ordered Both a MIM and RIM and will be attending outside of Trade hours , so I can take some precautions , but I just wondered if anyone may have some ideas on why it did that.

Best regards

Allan

[Battman_apc]

This was originally posted on APC forums on 9/29/2014

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Did you get the raw status data for the MIM and the RIM , or,  attempt or manage to download the log(s) out of the MIM / RIM to review before you attempted to put it into bypass the first time ? I am wondering if its possible that both the MIM and the RIM were both faulty prior to your first action to put it into bypass...if something major blew out on the MIM it could have caused collateral hidden damage to the RIM that didn't rear its ugly head until you tried the bypass operation / pulled the MIM. I had a case once where based on the display / LED's I thought the MIM was bad and pulled it when in fact the RIM was bad so the UPS went totally dead. Whenever I encounter a situation like this I find it very helpful to get an APC tech support person on the line before I do or try anything - they can take the raw status data, MIM / RIM logs and help identify exactly what has gone wrong.

[big_al_apc]

This was originally posted on APC forums on 9/30/2014

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Thank you both for much appreciated answers. I have replacement MIM and RIM units now,so tomorrow morning  I think the only option Ill have is shut the critical Systems off , Switch off the UPS and swap both units together. I think Battman could be correct that the RIM has been damaged as well. Then when I bring it back on line, we will see if the situation is really bad.

At least this way Ill get some kind of feedback. Unfortunately I do not have access to a APC tech support, (well My 2nd level does not), and Iam sure the owner would not either.

I will let you know what happens.

[Battman_apc]

This was originally posted on APC forums on 9/30/2014

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If from the sounds of it you are taking the UPS completely down / cold (input breaker shut off) to replace the MIM/RIM, as a precautionary measure you could at that time pull the symmetra communications card and whatever other accessory cards are plugged into the back of the unit and check for physical damage...you might also only want to bring the UPS up at first with only the new MIM installed;  in case something else inside the UPS may be damaged at least then you won't risk blowing both new modules simultaneously... Good Luck !

[big_al_apc]

This was originally posted on APC forums on 10/1/2014

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Success! I powered down the Unit from the rear CB. Removed the RIM and then installed new RIM and MIM. Switched on and after it started up checked the status of the Modules and Batteries and then took it out of ByPass. All good. I dismantled the MIM and as you can see a 5watt 2.7 ohm resistor is what blew up. The 2 watt Metal film Resistors there are also showing signs of stress and the two 56uF 450 Volt Electros appear swollen, so its on the way back to APC for repairs as is the RIM.

Thanks again for your Advise guys.

[Battman_apc · Accepted solution]

This was originally posted on APC forums on 10/3/2014

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Most likely the fault originated with the swollen capacitors...the swelling indicates they had broken down internally ( become resistive ) over time, perhaps from old age, perhaps accelerated by the UPS operating in a hot environment or could even be related to the world wide problem with faulty capacitors back in the 2000's...that means the caps are drawing/sinking more current and could have been contributor to blowing that resistor if its part of the current path.