Preamplifier, disk device, control device, and analysis method

A disk device comprising:

• a head assembly having a preamplifier;
• a casing housing the head assembly inside;
• a control device controlling the preamplifier;
• and
• a connection terminal exposed to outside of the casing and electrically connected to the control device,
• wherein the preamplifier includes:
• an abnormality detecting circuit connected to a structural element included in a head device of the head assembly;
• a reference resistance element having a resistance value corresponding to a resistance value of the structural element and connected to the abnormality detecting circuit;
• and
• a switching circuit switchable to a first state and a second state;
• wherein the first state is a state in which the abnormality detecting circuit and the structural element are connected to each other, and the abnormality detecting circuit and the reference resistance element are disconnected, and
• wherein the second state is a state in which the abnormality detecting circuit and the reference resistance element are connected to each other, and the abnormality detecting circuit and the structural element are disconnected.

A control device comprising a controller controlling a preamplifier included in a head assembly of a disk device,

• wherein the preamplifier includes:
• an abnormality detecting circuit connected to a structural element included in a head device of the head assembly;
• a reference resistance element having a resistance value corresponding to a resistance value of the structural element and connected to the abnormality detecting circuit;
• and a switching circuit switchable to a first state and a second state,
• wherein the first state is a state in which the abnormality detecting circuit and the structural element are connected to each other, and the abnormality detecting circuit and the reference resistance element are disconnected,
• wherein the second state is a state in which the abnormality detecting circuit and the reference resistance element are connected to each other, and the abnormality detecting circuit and the structural element are disconnected, and
• wherein the controller is configured to switch the switching circuit to the second state in a case in which the abnormality detecting circuit has detected an abnormality in a case in which the switching circuit is in the first state.

An analysis method comprising analyzing an abnormality detected by a preamplifier included in a head assembly of a disk device,

• wherein the preamplifier includes:
• an abnormality detecting circuit connected to a structural element included in a head device of the head assembly;
• a reference resistance element having a resistance value corresponding to a resistance value of the structural element and connected to the abnormality detecting circuit;
• and a switching circuit switchable to a first state and a second state,
• wherein the first state is a state in which the abnormality detecting circuit and the structural element are connected to each other, and the abnormality detecting circuit and the reference resistance element are disconnected,
• wherein the second state is a state in which the abnormality detecting circuit and the reference resistance element are connected to each other, and the abnormality detecting circuit and the structural element are disconnected, and
• wherein the analyzing of the abnormality includes switching the switching circuit to the second state in a case in which the abnormality detecting circuit has detected an abnormality in a case in which the switching circuit is in the first state.