To solve the problems that when the power failure of electronic equipment referring to a battery backup RAM for storing various operation parameters or data continues for a long time, the battery backup goes out, and the contents of the RAM breaks down, and when the power is turned on in that status, the electronic equipment operates while referring to the values of broken parameters of the the volume of an opening melody, the contrast of a display LCD and back-light setting, and the melody is heard with the maximum volume, or the melody becomes difficult to hear to, or display becomes difficult to view.

The contents of an RAM are checked when power is turned on, and until check ends, this electronic equipment is made to operate while referring to the initial value of a parameter stored in an ROM, and when the check result is normal, the electronic equipment is made to operate while referring to data stored in the RAM, and when the check result is abnormal, the electronic equipment is made to operate while referring to the parameter stored in the ROM after reflecting it on the parameter of the RAM.