It look like dead battery. Try to connect carefully new (or allmost new) battery with 24v lamp in (+) wire. If UPS alive - you'll see only small momentary sparcle. After this - connect battery as usual and try to turn system on. Be carefull! If lamp lit in full power - it means a serious internal problem. Best solution - look for qualified serviceman. (maybe yoir system needs reprpogramming).
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It look like dead battery. Try to connect carefully new (or allmost new) battery with 24v lamp in (+) wire. If UPS alive - you'll see only small momentary sparcle. After this - connect battery as usual and try to turn system on. Be carefull! If lamp lit in full power - it means a serious internal problem. Best solution - look for qualified serviceman. (maybe yoir system needs reprpogramming).