DEAR When no voltage 235 volts at the entrance to UPS, the UPS output from the device, the voltage is about 165 volts when the device runs on batteries ... At the moment of arrival voltage of 235 volts, the UPS failed its output the same voltage. Completed the replacement battery, and put the batteries from 12V 9 AH. two pieces, which I connected the serial. And afterwards, when the UPS runs on batteries as well, I still have a voltage of less than 165 volts at the output, instead of planned 230 volts. Is the problem in one of the components on the printed circuit board, or it may be a problem in the transformer? Thank in advance .... Dragoljub Gajic Belgrade SERBIA

Hello from America Dragoljub!

I can give you a general answer. I have not worked with this specific Mustek UPS, so the answer will not be specific. However, it should be enough information to help you to fix the problem. I work daily with many UPS and this is a common problem.

I do not believe that you have an equipment problem. It looks to be a configuration problem.

This is very often because of the UPS setup. When the UPS is configured, an output voltage must be selected. It appears that your UPS is configured for USA output voltage (120 volts RMS, about 165 volts peak measurement).

I am sorry that I do not have specifics to tell you how to configure your UPS. This information should be enough to help you solve your problem, though. Consult your UPS manual and find how to re-configure your UPS for 235 volts output and you will be OK.

Good Luck, and Thank You for using FixYa!

Vic