I NEED HELP FOR FIX THIS UNIT, CAN HELP ME? THANKS.

PROBLEMS: 1.- THIS UNIT IS PROGRAMMED TO OPERATE AT -80 C, WHEN STARTING ITS WORK IT REACHES -40 C AND STAYS THERE FOR A LONG TIME TWO OR THREE DAYS AND THEN IT CONTINUES TO LOWER THE TEMPERATURE UNTIL THE PRESET TEMPERATURE OF -80 C IS REACHED. 2.- WHEN IT HAS ALREADY REACHED THE PRESET TEMPERATURE (-80 C), THEY KEEP IN OPERATION WITHOUT PROBLEM FOR THE WHOLE TIME. IF THE UNIT IS OPENED AND THE TEMPERATURE LOWS TO - 70 C - 60 C DUE TO HAVING THE DOOR OPEN FOR TOO LONG TIME, IT WILL RECOVER QUICKLY WITHOUT PROBLEM, BUT IF IT IS OPENED AND LOSS TEMPERATURE AND REACHES -40 C THE SITUATION IS REPEATED, IT WILL STAY AT THAT TEMPERATURE OF -40 C, AND IN TWO OR THREE DAYS THE SYSTEM WILL REACH THE PRESET TEMPERATURE OF -80 C. 3.-THE MONITORING SYSTEM INSISTENTLY INDICATES IT DOES NOT HAVE ACCESS TO THE SD CARD BELOW IS AN IMAGE OF THE SCREEN. 4.- THE SD MEMORY WAS REMOVED AND REINSTALLED AGAIN WITHOUT BEING ABLE TO REMOVE THE NO ACCESS TO THE MEMORY LEGEND 5.- I VERIFY THAT THE SAFE TO WRITE ABOUT IT IS ENABLED WAS REMOVED IN THE SD MEMORY WITHOUT ACHIEVING RESULTS. 6.- THE INFORMATION OF THE EVENTS REGISTERED IN THE MEMORY SD WAS COPIED WITHOUT PROBLEM, IF YOU REQUIRE THEM, I CAN SEND THEM. I NEED SUPPORT FOR FOLLOWING: 1.-OPERATION MANUAL 2.-SERVICE MANUALS 3.- ADVICE FOR THE REPAIR OF THESE EQUIPMENT. 4.-REPLACEMENT PARTS NECESSARY FOR ITS REPAIR. 5.-ANY SUGGESTIONS IS GOOD. THANKS. EXCELLENT DAY M. ORTIZ