microsoft said:
I need to get data off some old 5 1/4" floppy disks and
archived onto cd. I have an old floppy drive (CHINON FR-506)
that is supposed to be a 1.2Mb drive.
If I set it up as 1.2Mb in the BIOS, I get the FLOPPY DISK(S)
FAIL (40) error at boot. If I leave it as 360kb, I don't get
that error. this makes me think it's a 360kb.
But if I try to read a 360kb disk I get GENERAL FAILURE READING
DRIVE A errors. I have another 360kb floppy drive that just
formatted this floppy.
There are some jumpers on the CHINON 1.2Mb drive that I'm not
sure if I need to fiddle with to get this drive working.
I'm using DOS 6.22, with the floppy drive as the only one on
the cable, at the end slot.
I'm rather sure that your drive is a 1.2M.
If the drive doesn't work even without a floppy in it:
Look for cable or drive selection problems. If the drive light stays
on all the time, then the data cable is plugged in backwards, but if
it turns on and off, then the drive may be plugged into the wrong
connector, or its drive selection jumper is set wrong. The IBM PC
standard calls for configuring all floppy drives as the 2nd one and
using twists in the cable to differentiate between A: and B:, and it's
possible that your 1.2M's drive select jumper needs to be changed.
Look for jumpers labelled DS0, DS1, DS2 or D0, D1, D2. If this jumper
was correct, then the drive may not be plugged into the correct
connector; it needs to go into the one just after the FIRST twist in
the cable, and that may be the socket at the end or the one in the
middle.
If the drive light turns on and off and you can hear the heads move:
Many 5.25" drives used a removable terminator resistor pack in a
10-pin or 14-pin socket, and one of the drives on a cable requires
termination or else the signals will be dirty. Plugging a 3.5" floppy
drive to the unused connector and the power connector should provide
necessary termination, but if not try finding a terminator pack or
connecting an approximately 1,000 ohm resistor between each signal
line and +5V (probably one of the pins at the end or a corner of the
socket). The terminator pack usually consists of pairs of 220 and 330
ohm resistors, and never have more than one such pack on any cable or
you'll overload the signals. Newer drives, especially those with
terminator packs permanently soldered in, use 1,000-ohm terminator
packs, and it's OK to have more than one of these per cable.
1.2M drives can work in high density (1.2M) and low density (360K)
modes, selectable by a high/low DENSITY signal on pin 2. But this
signal isn't used with 3.5" drives, except very old ones, and about
every floppy controller made in the past 10 years doesn't generate the
DENSITY signal when accessing a 3.5" drive. It's possible that your
floppy controller doesn't generate this signal even for 1.2M drives,
in which case the only solution I can think of is to cover pin 2 on
the drive with Scotch tape. Another possibility is that your 1.2M
drive has its DENSITY signal set for opposite polarity than normal,
but there may be a drive jumper to change this.
Another troublesome signal is on pin 34. With 3.5" drives it serves
as Disk_Changed (DC) status, but with 5.25" drives its function
varies. It may be unused, always on, or returns READY status (RY or
RDY) indicating that the drive has been selected and a disk is
spinning in it. If you can't set a jumper to make pin 34 give
Disk_Changed status, then cover it with Scotch tape
and use CTRL-C when you change disks, or edit CONFIG.SYS to add a
DRIVPARM line for the drive and leave out its "/C" parameter (use of
this parameter causes Disk_Changed to be ignored).
Are you using the proper disks? 1.2M disks usually work at 360K, but
360K disks never work reliably at 1.2M. 1.2M disks normally have no
reinforcement ring around the large center hole, but there are
exceptions, and a better way to distinguish disks is by looking
through the oval read/write hole and shining a strong light from the
opposite side. Real 1.2M disks are transparent red, as are 1.44M
disks, while 360K and 720K disks are opaque.
