APC BackUPS LS-500 Schematics?

[cook]

Asking for schematic and/or boardview for APC BackUPS LS-500.
Board number: 640-0236J-13

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

Can you please post some pictures of the board front and back so can read part numbers
We might be able help you fix it

[cook]

Re: APC BackUPS LS-500 Schematics?

The pictures are below. I tried to get the best resolution I could.

From left to right..
#1. Top Left of the board
#2. Top Right
#3. Bottom side of #1
#4. Bottom side of #2

[cook]

Re: APC BackUPS LS-500 Schematics?

Here is the problem I am working on with this UPS. Sometimes, only for a second or 2, the 'bad battery' light flash and it will beep. I have tried different batteries, and it still does it. I have tried a brand new battery, and it still does it. It may show the fault once every 5 minutes, sometimes more frequently, sometimes less frequently. It does this when something is plugged into it, and when nothing is plugged into it. When the UPS is running I am getting a good voltage at the battery, 13.69 volts. When the new battery is unplugged from the UPS, it reads 13.7 volts. The new battery has charged for 24 hours.
Thanks

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

Will this battery backup work with a 100 watt incandescent light bulb load with no 110 line voltage hooked up

It should turn if you hold power on button for about 5 second or so ———> if not try this hook it up 110 volt line voltage then after it does it self check if has one then unplug it from the wall dose the light bulb stay light if not then you have a problem with the power switch over circuit

[cook]

Re: APC BackUPS LS-500 Schematics?

Yes, it works fine with a 100W light bulb running on the battery. I could see the light pulse just slightly, but it ran the bulb just fine. I ran it a few minutes.

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

Okay

While you had the 100 watt bulb running on battery power did the low battery warning flash on or did even come on while you were doing this test

Look at the fault light wiring and trace where it goes on the circuit board until you reach a ic chip or some type of device and look up the device to see what it does then see if there is a capacitor near that device that goes to that device and replace them if there is more one capacitor

also trace the battery terminals back to some type of voltage monitor circuit on this board and if you find any capacitor replace them as well but before you buy anything mark where these capacitor are on the board

[budm]

Re: APC BackUPS LS-500 Schematics?

How many Watts is your actual load that you were having problem with? Notes: I am not talking about the 100W bulb.
You can also add another 100W load to see what happen.

[cook]

Re: APC BackUPS LS-500 Schematics?

Okay

While you had the 100 watt bulb running on battery power did the low battery warning flash on or did even come on while you were doing this test

Look at the fault light wiring and trace where it goes on the circuit board until you reach a ic chip or some type of device and look up the device to see what it does then see if there is a capacitor near that device that goes to that device and replace them if there is more one capacitor

also trace the battery terminals back to some type of voltage monitor circuit on this board and if you find any capacitor replace them as well but before you buy anything mark where these capacitor are on the board

The 'replace battery' light did not come on during the test.

I will get a list of the ICs on the board and post them in order to help me figure out what chip might be responsible for the 'Battery Replace' alarm. I will get that together later today. Knowing which chip might be responsible for that will give me 2 ways to track down the capacitors on the circuit -- tracing back from the LED and tracing from the IC.

[cook]

Re: APC BackUPS LS-500 Schematics?

How many Watts is your actual load that you were having problem with? Notes: I am not talking about the 100W bulb.
You can also add another 100W load to see what happen.

The 'Replace Battery' alarm comes on with a load, and without any load.

I will find a more items to plug into it and run it to see if anything changes. I will run it plugged in to AC, and running on the battery.

[cook]

Re: APC BackUPS LS-500 Schematics?

Chips On The Board
APC BackUPS LS-500 / Model BP500UC / Board number: 640-0236J-13

Below are the ICs on the board. I looked up each one and I listed what I found about them.

Which ones might be part of the circuit that triggers the 'Replace Battery' alert? I am thinking it is one or both of the 'LMxxx' chips maybe?

---------
BIG CHIP
The largest chip has a white APC sticker
on top of it listing it is for a 350/500/700
unit, along with a version number. So I am not
sure what that is. Maybe ROM?
---------
360-2040B
UEWJ0414
What is this?
---------
93LC46B
EEPROM
---------
SN74HC595N
8-bit, serial in, parallel out shift register
Is this for the USB connection?
---------
LM393N
Two independent voltage comparators
---------
LM324AN
Four independent operational amplifiers (op amp)
---------
4N25
Single channel phototransistor coupler
---------

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

Chips On The Board
APC BackUPS LS-500 / Model BP500UC / Board number: 640-0236J-13

Below are the ICs on the board. I looked up each one and I listed what I found about them.

Which ones might be part of the circuit that triggers the 'Replace Battery' alert? I am thinking it is one or both of the 'LMxxx' chips maybe?

---------
BIG CHIP
The largest chip has a white APC sticker
on top of it listing it is for a 350/500/700
unit, along with a version number. So I am not
sure what that is. Maybe ROM? ( if any pin goes any devices below that I made comments about then replace all capacitors that connects to any pin on this device )
---------
360-2040B
UEWJ0414
What is this? ( does any pin of this chip go to any of following devices below if they do then replace all around this chip
---------
93LC46B
EEPROM. ————
---------
SN74HC595N
8-bit, serial in, parallel out shift register
Is this for the USB connection?
---------
LM393N
Two independent voltage comparators. ( Replace capacitors if they go to any pins on this chip )
---------
LM324AN
Four independent operational amplifiers (op amp) ( Replace any capacitor that goes any pin to this chip )
---------
4N25
Single channel phototransistor coupler ( most important capacitor to change if any pin has a capacitor to it )
---------

See above for my comments

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

The 'Replace Battery' alarm comes on with a load, and without any load.

I will find a more items to plug into it and run it to see if anything changes. I will run it plugged in to AC, and running on the battery.

I was afraid of this that this might have been the case thanks for sharing this information

[cook]

Re: APC BackUPS LS-500 Schematics?

How many Watts is your actual load that you were having problem with? Notes: I am not talking about the 100W bulb.
You can also add another 100W load to see what happen.

I ran it connected to AC, running these lights: 40 watt incandescent, 60 watt incandescent, and a 150 watt halogen. The 'replace battery' LED came on briefly about 2 minutes into the test, then 5 minutes later, then 3 minutes later. Then I turned off the power to the AC, and it switched to battery. It runs fine on battery and the 'replace battery' LED does not go on. I ran it about 5 minutes like this and then stopped the test.

[CapLeaker]

Re: APC BackUPS LS-500 Schematics?

Got across this schematic today while doing backups. Hope this helps.

BTW: on your second picture there are 2 relays and 2 brown capacitors. The top brown capacitor looks to me bad.

[cook]

Re: APC BackUPS LS-500 Schematics?

Got across this schematic today while doing backups. Hope this helps.

BTW: on your second picture there are 2 relays and 2 brown capacitors. The top brown capacitor looks to me bad.

Thank you for the schematics!!

And thank you for noting that cap. I just looked closely at it, and it is has a slight depression across part of the top. It almost looks like something pushed into it because the metal on the top appears to have a small scratch or depression in the metal like something sharp pushed it in. It might even have a tiny hole in it, but I am not positive. I will certainly test that one further to see how it looks. It is a KMG Cap, ie. Nippon Chemi-Con

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

Got across this schematic today while doing backups. Hope this helps.

BTW: on your second picture there are 2 relays and 2 brown capacitors. The top brown capacitor looks to me bad.

The circuit diagram that you posted I only find one relay not two of them and I look for it for a while

[CapLeaker]

Re: APC BackUPS LS-500 Schematics?

I know that this schematic I posted above isn't the exact match, but it should be good enough to give an idea what is going on.

For me, I'd ESR the sh*t out of them caps and replace them. I've had a run in with my small SMT a few years back, it turned itself off all the time.
https://www.badcaps.net/forum/showthread.php?t=66277

I'd change the two brown caps, the 2 black caps next to it and C51 and retest.

[sam_sam_sam]

Re: APC BackUPS LS-500 Schematics?

For me, I'd ESR the sh*t out of them caps and replace them.

I would recommend this as well I more or less said the same thing earlier

[cook]

Re: APC BackUPS LS-500 Schematics?

sam_sam_sam,

I am currently identifying what capacitors are connected to the pins on the chips.

Am I only interested in the caps that are first component I find on the trace, or should I be going further down the trace through a few components?