UPS repair - Any suggestions?

[AndersJ]

Mini Guard Series UPS does not turn on.
It behaves as if it does not see the battery or the incoming AC mains.
Does anyone have any experience, or a schematic diagram?
The display shown below does not appear.
Only the backlight is on, while button is pressed.

[Dbn281977]

I have no experience on this brand but, the ones i do repair are very heavy duty units and 90% of them i repair, the fuses to the battery bank are blown ans several MOSFETs are bad usually a dead short. I replace them and the fuses , never had anymore problems with the unit. Hope that points you in the right direction.

[Gregg]

It may not turn on unless it senses a minimum DC voltage on the battery bus.  This is to keep from bursting bad batteries that may not take a charge.  If the battery fuses are intact, check the connections; if a lead acid battery has leaked, the corrosion can creep up the wire under the insulation and ruin crimp connections and even bolted connections.