In this article, I will share with you a method for diagnosing and troubleshooting an uninterruptible power supply (UPS). So why might the uninterruptible power supply not turn on or not work from the network? one of the first reasons, a fuse has blown, perhaps the transformer or control board has failed, but in our case it’s a slightly different, but at the same time very basic problem...
Let's take a closer look...
We repair an uninterruptible power supply with our own hands
At the very beginning, before disassembling, we need to check whether the fuse is working, usually it is located on the back side of the UPS
We remove it and check it using multimeter in call mode.
In this case the fuse is good.
Let's move on to disassembling the uninterruptible power supply (UPS) itself.
I would like to note that the disassembly method may be distinguishable from your UPS model, but should not cause you any particular difficulties in disassembling.
Unscrew 4 screws and remove the lower part of the UPS housing.
After disassembly, carefully inspect the board for external damage to components. In our case, no damage was found.
The first step is to check the battery.Let's measure its voltage with a multimeter.
In our case, the battery is discharged to 2 volts, which is naturally not good and is a fairly deep discharge.
Let's check the battery for charge and discharge by connecting it to a laboratory power supply for recharging to eliminate the possibility of its breakdown.
As it turned out, the battery refused to accept the charge from the laboratory power supply, which means that there is a break somewhere and, accordingly, our battery is not working properly.
Let's take another battery to check. In my case it has a slightly larger capacity. Accordingly, the uninterruptible power supply should hold its charge longer and fits perfectly into the UPS case!
We connect the terminals - let's run it for a test without assembling the case. Started up.
We measure its voltage: - 12.4 volts.
To make sure that the battery is charging, measure the voltage at the battery terminals for a few seconds with the UPS connected to the network. The voltage should gradually rise.
12.9 volts tells us that the battery is charging, the uninterruptible power supply is working, it can be assembled and put into operation.
Failure of the battery or loss of its energy capacity is one of the most common failures among all types of UPS. So don’t rush to throw them away right away.
