MAGNETIC RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To prevent the decrease in a reproduced output due to the expiration of the service life of a magneto-resistance effect magnetic head and the increase in noise in advance by measuring the change in the lapse of time in the total DC resistance of a magneto-resistance effect element. CONSTITUTION:A resistance detection circuit 5 detects the total DC resistance R0 of the magneto-resistance effect element 1 at the start of operation of a magnetic recording and reproducing device and stores the result in a service life discrimination circuit 6. Then the change in the lapse of time in the total DC resistance of the element 1 is detected by the circuit 5 and the circuit 6 repeats the comparison between a detected value R' by the circuit 5 and the total DC resistance R0 and discriminates it as the expiration of the service life of the element 1 when a value (R'-R0)/R0 reaches 5-30%. Then the magneto-resistance effect magnetic head discriminated to be at the end of the service life is replaced into a new head. Thus, the rapid decrease in the output voltage and the rapid increase in noise caused by the expiration of the service life are prevented in advance and the reproducing device is reutilized without any trouble.