try to open it and examin all fuses first, because that may be one or two fuses inside main board are blown. See if the rectifier is working, theck first inputAC voltage, than DC output voltage, see if DC capacitor are good (no explosion). if not, that means a soft problem, in this cas you can't do any thing, yu have to call specilist to fix it, he may do sofware upgrad, or change electronic card.
Thanks for the reply. I cheked all the above and I found that the problem comes from the dc booster from batteries to the bulk electrolytic capacitors.I am going to check the circuit around.