Screaming SUA750RM2U

[cernst_apc]

This was originally posted on APC forums on 8/10/2009

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I have had something interesting happen to me twice now with SUA750RM2U units. I manage about 100 of these over the network and have a rotating inventory.

The last one this happened to is a 2006 model, week 36, so I know it is out of warranty. When I first had it, I put a fresh battery pack in it and sent it out to a field location. It was packaged very well, no movement, plenty of padding. When it got to the location, the moment the battery is plugged in (so it can power on) and the power plug is plugged into the wall...it just sits there screaming. You can turn it on and it works just fine. I put an AP9606 card in it and all voltages/capacities were just fine, nothing out of the ordinary. There were no alarms or alerts on the front panel or reported by the web card. All lights on the front panel work. There is no load on the device. you don't even have to turn it on, just connect the battery and plug it in and it will start screaming constantly.

This is the 2nd one I've had this happen to and cannot figure out why this is happening. I've taken the top off and visually inspected the components...nothing appears to have fried. Capacitors are not puffy. Transformer is securely in place.

[Techie_apc]

This was originally posted on APC forums on 8/10/2009

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Corey,

I believe that there is an internal fault in the UPS circuitry as it should not act this way. As Power Man said, you will need to send the unit for repair or needs to be replaced.

[cernst_apc]

This was originally posted on APC forums on 8/10/2009

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thanks guys, I kinda had that feeling, but thought I'd ask anyway.

I'll salvage all parts I can off of it and throw it on my future trade-ups pile.

[BillP]

This reply was originally posted by Anonymous on APC forums on 8/10/2009

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Hi Corey,

It sounds like there may be a fault/damage on the controller. Have you tried to Brain Dead it (unplug it from the wall and hold the power button for about 10 seconds or until you hear a click in the unit)? If so then this may need to be replaced. Given the age of the unit I would suggest a Trade-UPS if the fautl continues.

[cernst_apc · Accepted solution]

This was originally posted on APC forums on 8/10/2009

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yeah, I've completely discharged the unit, still screams.

I've played with it a bit more. If I only connect the battery and start it using battery power, it doesn't scream until I hit the on button.