I use a strobe disk glued to a fridge magnet that I stick on the spindle
motor of 5 1/4" drives to confirm the speed; the trouble is that it's
becoming difficult these days to find lamps that emit light at 60 Hz. ;-)
On Sun, Nov 3, 2024 at 10:21 PM Chuck Guzis via cctalk <
cctalk(a)classiccmp.org> wrote:
On 11/3/24 18:44, Fred Cisin via cctalk wrote:
On Sun, 3 Nov 2024, Steve Lewis via cctalk
wrote:
> Non-descript 5.25 DS/DD (they don't format as 1.2M disk using a 1.2
> 5.25"
> drive, so I'm pretty sure they are actual 360KB disks). That said, I
> haven't really fully confirmed if it's a 1.2M drive. TEAC FD-55GFR
> 142-U, because I haven't actually come across any 1.2M formatted media.
> I've wondered if maybe one of the heads on the D: drive the Sharp
> PC-5000's
> dual disk drive might have some kind of issue (either the REad or Write
> head, not sure which) - just since it seemed more likely to end up with
> some bad sectors marked when using
FORMAT.COM (whereas on other
systems,
the same
disk would format fine with no bad sectors).
Teac FD-55GFR is a 1.2M drive that can also be used as a 720K 5.25"
drive.
(FD-55G is 1.2M; FD-55F is 720K)
Just be sure to set the drive jumpers so that the spindle speed is 300
RPM, not 360, which is the usual default for PC drives.
--Chuck