Allview Speed City (onda v701) problem topic

I installed a firmware that was made for a slight different tablet (city+) on my speed city (onda 701) tablet using AmlogicBurningTool. everything went fine, it was a succes but after I turned on my tablet i saw that the the display was all white, with some multicolored lines on it. I can't do anything with it now. Flashing another firmware is impossible because it's not detected by the PC anymore if it's turned off. help me please.