Does anyone know if that light bulb is still available? I’m not sure what the response of that photo sensor is and that might rule out using a led replacement. The fact that the bulb is almost certainty driven below the rated voltage also complicates matters.
Marc On Tue, Jan 17, 2023 at 5:10 PM Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > On 1/17/23 13:58, Paul Koning via cctalk wrote: > > > > 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. > > > And, IIRC, a bit red warning sticker on the actuator. > > --Chuck >
