17 Jan
2023
17 Jan
'23
7:18 p.m.
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(a)classiccmp.org> wrote:
On 1/17/23 13:58, Paul Koning via cctalk wrote:
And, IIRC, a bit red warning sticker on the actuator.
--Chuck
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.