| 摘要 |
PURPOSE:To find out earlier an abnormal magnetic head having a grounding fault by providing independently respectively a constant voltage driving circuit giving a potential to a center tap of a magnetic head at each magnetic head so as to provide a potential only to an accessed magnetic head. CONSTITUTION:Constant voltage driving circuits 9, 10 giving a voltage of a constant voltage power supply 1 to magentic heads 5, 6, 7 and 8 are provided by the number of magentic heads. Further, circuits consisting each of a transistor TR3 are provided by the number of plural heads IC3 and 4. When the magnetic head 5 is selected for example and write is started, even if the magnetic head 8 has a grounding fault, since the magnetic head 8 has no potential, no problem is arisen. If a grounding fault takes place in the magnetic head 5, a voltage drop of the constant voltage power supply 1 due to a short-circuit current is detected by a comparator 2 and a detecting signal is transmitted to AND circuits 12, 13. Thus, the destruction of data after recording because of a magnetic head producing the grounding fault is prevented in this way, and the magnetic head causing the grounding fault is detected suitably. |
