APC UPS ES 500 keeps on beeping

hello there, I am working in one of the company here in the phil. they have this APC ES 500 UPS and when it is turned on after 5 seconds it will keep on beeping. I've tried to disconnect the battery and tested it via multitester and it still has around 12 V on it. I mounted the battery again, connect it to the outlet, turned in on, tested the outputs of the UPS and it works fine. The only thing that is abnormal is it keeps on beeping after 5 sec. after it has turned on.....HELP please!

Hi,
can you tell me ,when it's turn on display coming or not? if not means it's a memory problem.if display OK but beep sound coming means it may be keyboard key problem.try to run memory test first.take out all your important data's before........8O

what memory/display?.....i am talking about uninterruptible power supply(UPS).
when i turned on the UPS the green light indicator is ok then after about 5 seconds it keeps on flashing together with the beeping.

hello your prob will be solved by replacing eeprom ic in apc which is of 24cxx smd component.after that it will give 4 beeps at perfect intervals.

There is no memory inside this UPS. It is normal fault with APC inverters. And this beep, when decoded, gives imbalance of battery charge. If you have diagram, locate the series resistor for sensing the charging and current. Thats the only problem. I have came across this fault in about more than 10 inverters.
I am attaching here one schematic of APC UPS 500, though it may not be exact model but can help you. Give one try by replacing LM339.
View attachment APC UPS500.pdf

Good Luck.

Raza said:

There is no memory inside this UPS. It is normal fault with APC inverters. And this beep, when decoded, gives imbalance of battery charge. If you have diagram, locate the series resistor for sensing the charging and current. Thats the only problem. I have came across this fault in about more than 10 inverters.
I am attaching here one schematic of APC UPS 500, though it may not be exact model but can help you. Give one try by replacing LM339.
View attachment 65310

Good Luck.

Click to expand...

Hi Raza, I have the problem as following detail, I am not sure that it is the same problem indicator that I can use your solutions, could you help?

1. When never open APC ES-500 (model BE500R-AS) with plug-in to outlet (220V) it will have the continues Beepppppppppppppppppp with the Green LED blinking. In during Beepppppppppppppppppp Alam, I still able to plug my load and use it as normal. (only Beeppppppppppppppp is very annoying)

2. When I un-plug outlet (220v) the Beepppppppppppppppppppppp is gone but only, normal state of using battery as 4 Beep and Geen LED suspend once during Beep sound.

3. When I open the PCB, I could not find the IC LM339 as you suggestion (I understand that difference Schematic to be refer) but I found only LM324AN as link of image capture below. So I am not sure, if I change this IC the problem would be solve as the same as you mention above?

Image of PCB and IC for your reference
1. https://www.dropbox.com/s/io6v0cakovpa8uv/2013-02-16 11.27.39.jpg
2. https://www.dropbox.com/s/fgp9n1ywv2h0iwb/2013-02-16 11.32.17.jpg

Please advise and Thank in Advance.

Regards,

I saw the PCB, it is different model. LM339 and LM324 are quad OPAMPS with little difference in design. This beep seems to be indicationg battery over charge alarm (a false one) and leads to a bad LM324. If visually no indication of any damage, I can suggest only (without physically examining) try changing the LM324 and see the result. If problem gone Enjoy and if not please tell me.

- - - Updated - - -

I saw the PCB, it is different model. LM339 and LM324 are quad OPAMPS with little difference in design. This beep seems to be indicating battery over charge alarm (a false one) and leads to a bad LM324. If visually no indication of any damage, I can suggest only (without physically examining) try changing the LM324 and see the result. If problem gone Enjoy and if not please tell me.

Hi Raza,

Yes, I will test it on coming holiday, and I will let you know the result.

Thank you every much,

Hi Raza,

After I have replace the LM324AN as per advised, now it works. I can repair it now. Just for you info. I replace the LM324AN with LM324N. It still work find. I have look into the IC specification, what was difference is the Current - Supply. LM324AN is 1.5mA but LM324N is 1mA.

If it broken again, I will note to change the same IC number

Thank you very much. It was very grateful advise
Also Thank you EDABOARD.com as well for the place to meet the kindness and guru people here

Raza said:

I saw the PCB, it is different model. LM339 and LM324 are quad OPAMPS with little difference in design. This beep seems to be indicationg battery over charge alarm (a false one) and leads to a bad LM324. If visually no indication of any damage, I can suggest only (without physically examining) try changing the LM324 and see the result. If problem gone Enjoy and if not please tell me.

- - - Updated - - -

I saw the PCB, it is different model. LM339 and LM324 are quad OPAMPS with little difference in design. This beep seems to be indicating battery over charge alarm (a false one) and leads to a bad LM324. If visually no indication of any damage, I can suggest only (without physically examining) try changing the LM324 and see the result. If problem gone Enjoy and if not please tell me.

Click to expand...

Hi Raza,

Today, after I have changed LM324 for a week, now the problem is back again. What is cause the LM324 damage, could you give me an idea or solutions, pls.:-?

hi, i think your prob is on the sensing circuit,try changing resistors to low tolerence and consider temperature change may affect sen circuits.the design also locate heat producing component and add maybe a cooling fan ,good luck

hi try to replace the Adjustable Micropower Voltage Regulators...i done this many times..hope it helps

sir I think we have the same problem sir.

If there ae some variable resistors, change them with new ones.

no variable resistors for this model.