720K Floppy Drive desperately needed

  • Thread starter Thread starter Daniel Vonboles
  • Start date Start date
D

Daniel Vonboles

Hi all,

Does anyone have an old DD 720k (1Mb unformatted) 3.5" floppy drive or
an old computer housing one that you don't need? I am looking to
purchase one but cannot seem to find one anywhere.

Please let me know if you have one of these you would be willing to
sell or if you know where I can acquire one for a reasonable price.

Thank you very much.

Daniel Vonboles
 
a search using the term "720k floppy drive" yields these sources:
http://www.abcresellers.bigstep.com/item.html?PRID=1205593
http://www.futurebots.com/pcstuff.htm
http://www.cfusion.com/33F4930.htm
http://www.cfusion.com/ibmdrive.htm
Here's one that works with 1.44 and 720k diskettes:
http://www.etronics.com/product.asp?stk_code=S0438894&svbname=384
TEAC FD05PUB is fully compatible to Mac and PC systems. It reads and writes
1.44MB Mac diskettes as well as 1.44MB and 720K PC diskettes insuring that
your system can work with all your previous data. The FD05PUB floppy drive
utilizes the Universal Serial Bus (USB) interface connector that comes
standard on Mac and PC systems. The hot-swappable USB interface provides
plug and play convenience by eliminating the need to turn off or restart the
system when connecting. Its simple one-cable connector eliminates the need
for a separate power cord that's found on other drives. The FD05PUB is based
on TEAC's industry leading 3.5", 1.44MB floppy drive - the same drive that
found in many of today's leading desktop and notebook computers.

$56.69
Usually ships
within 1-2 Days

Sounds "reasonable" to me, Dan.
(a new part, too)

Pepperoni
 
Daniel Vonboles said:
Hi all,

Does anyone have an old DD 720k (1Mb unformatted) 3.5" floppy drive or
an old computer housing one that you don't need? I am looking to
purchase one but cannot seem to find one anywhere.

Please let me know if you have one of these you would be willing to
sell or if you know where I can acquire one for a reasonable price.

Thank you very much.

Daniel Vonboles
Click to expand...


check on the swap shop of:

www.obsoletecomputermuseum.org/helpline

if somone has one...they will prob. sell it for little more than the price
of postage

btw: you can format a 1.44 floppy as 720 if you tape over the hole that's
not the write protect
 
Does anyone have an old DD 720k (1Mb unformatted) 3.5" floppy drive
Click to expand...

I've never known of a case where a 1.44M wouldn't work in place oa a
720K drive if it was set up in the BIOS as a 720K and opaque tape
placed over the 2nd square hole in the floppy disk (on the right hand
side when inserting the disk into the drive).
 
do_not_spam_me said:
I've never known of a case where a 1.44M wouldn't work in place oa a
720K drive if it was set up in the BIOS as a 720K and opaque tape
placed over the 2nd square hole in the floppy disk (on the right hand
side when inserting the disk into the drive).
Click to expand...

If attempting to use old 720K disks, some were made from lower
coercivity magnetic material. The 720K drives had a wider read/record
head than do the 1.44M ones. This may give problems attempting to read
disks made in old drives on the old material. Some 720K disks used
magnetic material which worked fine at 1.44M. They used to sell punches
to put the extra hole in them. Your suggestion may work fine, depending
on what the OP is trying to do. It's sure worth a try!

Virg Wall
 
VWWall said:
do_not_spam_me wrote:

If attempting to use old 720K disks, some were made from lower
coercivity magnetic material. The 720K drives had a wider read/record
head than do the 1.44M ones. This may give problems attempting to read
disks made in old drives on the old material. Some 720K disks used
magnetic material which worked fine at 1.44M. They used to sell punches
to put the extra hole in them. Your suggestion may work fine, depending
on what the OP is trying to do. It's sure worth a try!
Click to expand...

The coercivities of the coatings on 3.5" 720K and 1.44M disks are
almost the same, within about 10% of one another, unlike the case with
the coatings on 5.25" 1.2M and lower density disks. But the grain
size and thickness of the 1.44M coating are only half (why those disks
are slightly transparent), and I've never gotten 100% reliability with
720K disks formatted to 1.44M. But I've never had problems with 1.44M
disks in 720K format, at least if I bulk erased them first. I used to
hack up floppy controllers to make them put out the high/low density
signal on pin 2 for 3.5" drives back when 720K was still widely used
and when 1.44M drives could be configured for this (most now require
the second hole for 1.44M/720K format selection).
 
do_not_spam_me said:
The coercivities of the coatings on 3.5" 720K and 1.44M disks are
almost the same, within about 10% of one another, unlike the case with
the coatings on 5.25" 1.2M and lower density disks. But the grain
size and thickness of the 1.44M coating are only half (why those disks
are slightly transparent), and I've never gotten 100% reliability with
720K disks formatted to 1.44M. But I've never had problems with 1.44M
disks in 720K format, at least if I bulk erased them first. I used to
hack up floppy controllers to make them put out the high/low density
signal on pin 2 for 3.5" drives back when 720K was still widely used
and when 1.44M drives could be configured for this (most now require
the second hole for 1.44M/720K format selection).
Click to expand...

It could well be the grain size, but the comment about the head gap
still applies. It was only a problem with disks written on early 720K
drives. You never knew just what a given disk contained. Some 5.25"
single sided disks were coated on both sides, and some 720K disks were
"fine grain" and worked just fine at 1.44M when a hole was punched.

Virg Wall
 
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