jkaidor@ (Jerome Kaidor) (12/22/90)
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Organization: SynOptics Communications Inc. Santa Clara, Ca.
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Can anyone help? I am trying to interface a 720K 3.5" floppy
drive to my PC. After getting all the wires right, I now find the PC
returning a "drive not ready" indication from this floppy. It seems
that there is some difference here from the 5.25" floppies, in terms
of the electrical interface signals. The computer is a "tiger-286 AXT
" card, which is a 286-based XT bus system. The BIOS looks at one of
the dip switches on the motherboard. If that dip switch is on, the
BIOS simulates "drive always ready", or something to that effect.
Anyway, with that switch on, the 720K drive works, but my good old
1.2Meg drive turns into a 360K drive! So my precise question is:
Which shugart-bus wire is the 720K drive leaving "not ready"? Thanks
in advance...
- Jerry Kaidor ( jkaidor@synoptics.com )hollen@megatek (Dion Hollenbeck) (12/28/90)
In article <22134@mvis1.com> jkaidor@ (Jerome Kaidor) writes: > > Can anyone help? I am trying to interface a 720K 3.5" floppy > drive to my PC. After getting all the wires right, I now find the PC > returning a "drive not ready" indication from this floppy. It seems > that there is some difference here from the 5.25" floppies, in terms > of the electrical interface signals. The computer is a "tiger-286 AXT > " card, which is a 286-based XT bus system. The BIOS looks at one of > the dip switches on the motherboard. If that dip switch is on, the > BIOS simulates "drive always ready", or something to that effect. > Anyway, with that switch on, the 720K drive works, but my good old > 1.2Meg drive turns into a 360K drive! So my precise question is: > Which shugart-bus wire is the 720K drive leaving "not ready"? Thanks > in advance... What you need to do is diddle with line 34. It is the last one on the (usually) top side of the edge connector on the floppy circuit board. Hopefully, close to the edge connector is a jumper block (or dip switch) which is labelled RDY. If so, just remove this jumper. It may also be on the jumper block (or dip) used to select which drive to use. If not, maybe you have two points labelled RDY with a wire soldered between them (trace the trace coming from 34 and see if it goes through some such place where a stake pin jumper could have been put, but just a wire was soldered). This can be cut, but don't do it yet. First try a trick to see if it will work. Get some black electrical tape and cut a piece about 3/32" long and then cut that so it is only 3/4 as long as it was. Carefully place this piece of tape over trace 34 on the edge connector so 1/4" is hanging out in space and the rest overlapping the trace so it is completely covered. Wrap the overhang onto the back of the connector. Carefully slip the edge connector back on and try your drive. If the problem went away, go back and cut the trace. This is permanent, so you will not EVER be able to use it on an XT which is expecting the opposite of an AT for the RDY signal. Make sure you take the tape out of the connector or it could get over on another signal and make the drive not work at all. -- Dion Hollenbeck (619) 455-5590 x2814 Megatek Corporation, 9645 Scranton Road, San Diego, CA 92121 uunet!megatek!hollen or hollen@megatek.uucp