[comp.sys.ibm.pc] Problem with my home brewed 360K ext. floppy drive

pwong@batcomputer.tn.cornell.edu (Patrick Wong) (03/06/90)

Hi, hardware Hackers:

My project is to build an external 360K floppy drive for my laptop.
I already mount an appropriate power supply in a metal case, which also
has room for the 360K floppy drive.  (Note that I am using an internal
360K drive and +5 +12 v power supply).  The cabling between the drive
and the laptop is definitely correct, I am certain.  Now the problem
is when I try the drive when it is still not installed in the metal
case, it works perfectly (i.e., it can read, write, format, etc.).
However, after I mount it in the case next to the power supply, it
boots alright and the laptop recognises its existence but I cannot
do a "dir" (or anything for that matter) to the diskette.  It keeps
saying "error reading disk...." or something.  As soon as I un-mount
the drive and put it not in contact with the case, it works again.

It seems like the drive does not like to be grounded with the 
power supply.  Can anybody tell me why? Or did I do something wrong ?
Obviously, the easy solution to this problem is to not letting the
drive come into contact with the case, like using some plastic spacers.
but I keep wondering why...

Patrick Wong  ------------------------>  pcw@squid.graphics.cornell.edu

Thanx in advance !