4X DDR4 Test Card RAM Memory Slot Out LED Desktop Motherboard Repair Analyzer Tester DDR4 testing CARDS fully the , for AMD all DDR4 interface board, use leds to indicate that the data line address line open circuit and short circuit. Short circuit fault If a lamp is not clear, Could memory and CPU holder or with short circuit, memory slot is damaged If a light, clear, must check the signal and power supply circuit Equipped with battery (CR2032, 3V) insert battery to insert the test card and insert into the corresponding type of motherboard, and insert the CPU motherboard, presses the switch button, test card can assess motherboard memory part of open circuit. Used to repair is not switched on, does not display, does not read failure such as motherboard, memory is an essential instrument for repair computer motherboard