XS1300G

[Anonymous user]

Tonight, the power went out briefly two times, and both times the UPS failed to prevent the computer from crashing.  It's less than a year old, I called tech support and was left ever so incredibly confused.  

I used to have another APC (model fails me right now) but it never failed me...  The tech mentioned I may need a unit with pure sine wave depending on my power supply..  I built the computer at the same time I bought this APC, so the computers components are pretty up to date..   

Any hints, tricks, tips..... ?

[Anonymous user · Accepted solution]

There are certain computer power supplies that can be incompatible with the most commonly available uninterruptible power supplies. Such power supplies contain what is known as an active power factor correction circuit. Not all power supplies having this feature demonstrate this incompatibility. Those that are incompatible will usually shut down suddenly (just like you turned the computer off by pulling the power cord out of the wall) when the UPS switches over to battery power.

When it switches over to battery, your XS1300G UPS outputs what is known as a "modified sine wave" instead of the true sine wave that your electrical utility delivers. Certain power supplies having active power factor correction circuits can't handle this change and shut down suddenly or behave erratically.

If your power supply has active power factor correction circuitry, it won't have a manual voltage selector switch on the back panel. Unfortunately, it's not a matter of how new or cutting edge the components are. There are still a few computer power supplies out there that just can't handle this and cause problems.

To test the UPS and verify that it works, you could try it with another computer or use a simple load like an incandescent lamp. Connect whatever load you want to use, turn the UPS on as you normally would with it plugged into the wall outlet, and then unplug the UPS from the wall outlet. If the test load stays running, the UPS is probably OK.

Of course, it wouldn't be a bad idea just to make sure the computer is really plugged into the battery backed outlets. I've certainly made that mistake a few times in the past.

If it turns out that your computer's power supply is incompatible, there are only two ways to cure it:

1. Get a UPS with a true sine wave output. APC's 750 VA and larger and Smart-UPS models have this capability.

2. Change the computer's power supply to a different make and model. Try to find out from the manufacturer or vendor if a modified sine wave UPS will cause problems.