11 Oct
2008
11 Oct
'08
11:51 p.m.
Chuck Guzis wrote:
Those full-height Sonys that I mentioned (which don't, of course, handle
HD media [1]) use mechanical sesnors for disk-inserted and write-protect,
which move little plastic 'flags' into slotted optoswitches. It wouldn't
suprise me if at least one HD sensor worked that way.
[1] The disk-inserted sensor pin lines up with the position of the 'HD
hole' so the drive thinks it has no disk if an HD one is put in. I have
been told this was deliberate, the HD media is of a higher coercivity
than the DD (altough much closer than the differnce between DD and HD
5.25" diks), so using the wrong disk may well not be reliable.
The first issue is to get the drive to ignore the
difference between
1.44MB and 720KB media
I think drives nearly always do the detection via a microswitch, don't they?
(It wouldn't surprise me if at least one wasn't using some kind of optical
arrangement). In the event of no jumper, cutting
traces or bridging switch
pins with solder should do the job I would have thought.
If the sensor is optical, then the same methods apply (cut a trace to
force it 'dark', short the phototransistor to force it 'light').
-tony