APC UPS ES 550 sparking sound

[Anonymous user]

I need help identifying this sound

My APC Back UPS ES 550 is making a horrendous clicking/sparking sound. The power led is flickering green (on). It's drawing 10w of power with nothing connected.

The noise could be coming from the speaker or 12v relay (845HN-2C-B-S). It's hard to distinguish since it's so loud and both components are close to each other. I don't see any damaged capacitors or blown fuses.

What is going on here? See the video for the full effect.

APC UPS ES 550 sparking sound - YouTube

[Anonymous user]

I need help identifying this sound

My APC Back UPS ES 550 is making a horrendous clicking/sparking sound. The power led is flickering green (on). It's drawing 10w of power with nothing connected.

The noise could be coming from the speaker or 12v relay (845HN-2C-B-S). It's hard to distinguish since it's so loud and both components are close to each other. I don't see any damaged capacitors or blown fuses.

What is going on here? See the video for the full effect.

APC UPS ES 550 sparking sound - YouTube

[BillP]

Hi sv3vster, I think the sound we're hearing in the video is that of a relay chattering between contacts. This is obviously not a normal condition. The rate at which it's changing states, would lead me to believe that we have a failure of the unit's intelligence. Can you please provide the exact model and serial number of the unit so I may make a recommendation? Thank you! Secretsquirrel

[Anonymous user]

Turns out it's a bit more difficult than expected to locate that defunct part. It is a double pole double throw (2NO/2NC) 12V 8A relay. I may have found a suitable drop in replacement. According to the data sheet, some of the pins are only off by a small margin. Please let me know your thoughts:

Part No: HF115F-012-2ZS4

(or older equivalent JQX-115F-012-2ZS4)

[BillP · Accepted solution]

Hi sv3nster, The rapid switching of the relay is likely a symptom of a corrupted EEPROM and not that of a faulty relay. I would recommend replacing the unit and forego any repairs. The unit is over 7yrs old and will likely continue to show symptoms of it's age. Best, Secretsquirrel