Jaycar Powertech 1500va UPS circuit/schematic

[pauln]

During a recent power outage my UPS failed to work!!  Anyway checking the batteries showed they we U/S.  Replaced and all seemed OK i.e. they charged up OK.  On test with a load connected the unit switches over OK - but shows no load % used, then shuts down after a couple on minutes.  The manual mentions if the UPS "appears to see no load" it will turn it self off after a minute or 2.  The unit appears to work otherwise i.e. the capacity decrements as expected.  So I guess if there is some way to turn off the "no load" option it would be a cheap fix, otherwise looking for ideas or circuit.
Thank You

[PeterG]

If you contact Jaycar they will most likely provide you with the schematic.

Regards

[pauln]

If you contact Jaycar they will most likely provide you with the schematic.

Regards

Already tried phone and email to Jaycar - and a personal request to local store - with out success.  Hence my post.