[cctalk] Re: Disk pack production tools

No, 844 drives use linear voice coils (linear motors), which seems to have become the norm in the early 1970s. RK05 is another example. The term "voice coil" is used because they look like oversized versions of the coil that drives the speaker cone in loudspeakers. These all are some sort of servo device; in many of them the servo signal is on the media, but not always. For example, the RK05 uses a pattern of lines on a glass substrate attached to the actuator; the "fault" light on the drive indicates a failure of the light bulb that illuminates the servo pattern. A common feature of linear motor actuators is an emergency retract circuit, powered by rather large capacitors, to pull the heads off the disk if there is a power failure.