The timer chip told the DMA chip to go into RAM and refresh the memory. The DMA chip did this, but the refresh process failed. The possible causes of this malfunction includes;(1) bad memory chip (2)a bad DMA chip, or (3) bad memory addressing chips on the motherboard. Turn off the computer, remove all the memory chips, and test them. Replace any bad chips and retest the computer. Since the DMA chip and the memory address logic chipa are almost always soldered to the motherboard, you will almost certainly have to replace the motherboard. Return to the main menu.