Arman Gungor's Blog Litigation Support and Technology

5Dec/105

APC Smart UPS Loud Beeping Problem

I have been using an APC SUA1000 at home for about 5 years. I have used other APC devices in the past and have always been happy with their build quality and performance. However, this unit has been giving me trouble lately. It all started about 2 years ago when I came back home from a long trip to find the UPS emitting a constant, loud, excruciating sound. The beeping did not stop when the UPS was turned off or its power cord was disconnected from the outlet. The only way to stop the noise was to either disconnect the battery or braindead the UPS.

After a few e-mail exchanges and phone calls with APC customer service, I was informed that my warranty had recently expired and my only option was to send the UPS for a repair at my own cost. I decided to open the unit's case and take a look inside to see if there was anything obviously wrong with it before shipping it for repair. I disconnected the batteries, looked inside the UPS and did not notice anything obvious. Closed the box, powered up again and to my surprise, the noise was gone. It passed self test and I tested it a few times under load by disconnecting it from the outlet and it continued to provide power without failure. I was able to use the device for another 2 years or so without any trouble.

Life was good again until the unit ran out of battery recently. I ordered a replacement APC battery and installed it. As soon as I turned the unit on, I was welcomed by the good old constant buzz. Went through the same process of opening the box and disconnecting the battery a few times without any luck. I also sent some messages to APC message boards and found out that there were at least a few more people with the same problem. Their UPSs (not only SUA1000 but other models such as SUA1500, SUA2200 etc.) appear to work perfectly fine except for the annoying noise.

Finally, not having been offered a viable explanation or solution by APC, I was forced to operate on my UPS. I opened the case again, located the piezoelectric buzzer (see picture) and de-soldered it. I am sure the UPS is still trying to emit the same sound but at least I am not hearing it. It has passed self test as well as my manual tests and has been powering my computer successfully for the past couple of days.

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  1. this is a great idea, thanks! and good job in finding that buzzer. ours is still working quietly but at least we know what to do now once it starts that annoying noice.

  2. Removing the buzzer will make “cold-starting” the UPS difficult because you need to hear the beep to know when to let go of the button, but otherwise a very useful idea. Incidentally, the buzzer in the SUA750XLI, and possibly other models, is accessible via the battery compartment. Using a pair of pliers, and a bit of care, the sounder can be wrenched off of the circuit board without causing any damage (except to the sounder itself!) and there is no need to even open the UPS casing :-)

  3. I slid mine out of the rack to try to open it and see if I could find the buzzer- slipped out of my hands with a loud thunk as it dropped on the concrete. Tone stopped! Working fine – so when all else fails – the Fonzi method works too!

  4. I recently put new RB7 to this UPS (1500 smart) and same problem arrived :/ Constant f…. sound, without any problem (like overloading etc). It looks like buzzer is constantly powered.
    It drives me crazy and APC seams not to see the problem or help customers to solve the problem even after warranty they should investigate the problem and post solving instructions.
    Got damn, I can desolder buzzer but I also want it to inform me when ups looses mains. Damn it, no solutions googled sofar :( – desoldering is not the solution i like.

  5. I have also suffer from this problem, that little sucker started to beep when I have removed all batteries and put new ones into APC SUA1500I… apc.com hot line told me to make a costly repair or but a new one with funny discount!!!!!
    I have googled for your tip but this makes UPS not working as it was desinged to :-) so the solution has been rejected. I hope you still have the buzzer around!
    One kind guy (thank you dude) gave me a super tip, so easy to do.
    Solder it back and check this solution: Make ups brain dead (out of mains, disconnect batteries and then press I on button for a while until you hear clik of the relay). Then remove front cover, take batteries out and look into the batteries compartment – look at the PCB and a uC chip (a chip 2x2cm or so – near the border – close to the front panel side). Gently press it around with a finger so it seats better in the socket. The problem should gone… I did not investigate into that (bad socket-uC contact or a bad solder socket-pcb) but the problem has been solved!!!! No more brain killing buzzing and full functionality is back!

    Other things to maintain – check with a voltmeter the float batteries charge/voltage (1hour after UPS tells 100% charge has been reached). You should have 13,65V , no more 13,80V and not less then 13,5 (above 13,8 is is to high, 13,5-13,8 is in the producer specification but batteries inside ups get warmer and the voltage should be decreased by temperature coefficient parameter which is around minus -20mV per battery/1C above 25C). If it is above 13,8 yout batteries cook inside, bubbling happens and you loose water… 13,65 is fine, near recommended 2,25-2,275 per cell (6 cells per battery).
    To change it on apc smart 1500 (does not work in all models – APC700 does not 4 example) you must enter PROG mode (google for it) and enter shift+B and then *with a voltmeter hooked to the battery – each battery should read that voltage,)* press + to make it lower, check voltmeter after while and reading should drop a bit. If you have a steady 13,65 or so reading shit+R exits PROG and viola!
    Other thing good to check is if batteries (both) have same voltage since they are connected in series. Each of them should be around 13,65 and very close to the reading of neighbour one. If not it is bad, one could be overcharged. Do the equalitization charge procedure (15V for no more then 2hours and you connect the batteries in parallel, yes 15V is way to much but we keep it for a while and it helps to make voltage spread even across the battery cell sets (12 cells in series) !!!!). Google for it also.
    I hope your UPS will now work like a charm and as a new one! I have also set proper SHIFT+L line voltage reading and shift+P power reading but it is better not to play with it and also write down former settings so you can always go back. Battery constant reset via “0″ function in PROG mode is also very recommended when you do not get expected runtime on a fresh set of batteries (Apc-fix program can do it for you). Now my UPS does not buzzzzzzzz, does not overcharge batteries, shows proper line Voltage and Power utilization via software…


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