3.5" floppy drive in IBM XT?

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Tue Apr 8 16:52:00 2003

On Tue, 8 Apr 2003, Joe wrote:

> The controller is full length and has XEBEC chips and a Z-80 CPU.
> I'm sure that it's MFM. It's marked IBM and next to that is a paper
> sticker that says #1501492. Also marked IBM 6135984 in copper foil. My
> diagnostic tool shows four settings in the ROM, the 10Mb drive is
> third setting. I didn't look at the capacity of the other settings.
> It's running this drive as a 10 Mb MFM drive but the drive is rated as
> a 32Mb RLL capable drive.

> my controller is an original IBM 10 Mb MFM HD controller. It's only
> using 10 Mb of the drive.

Near the middle of the board are 8 solder pads. By jumpering those (they
are the right size for a 4 position dip switch), you can get the
controller to use the other setting that are in its ROM. The 4 positions
are 2 for each drive, resulting in 4 possible combinations for each
drive. 10M, the default, is both switches open.

OR, there are software ways tio override the controller -
check with Steve Thatcher.
Received on Tue Apr 08 2003 - 16:52:00 BST

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