8 Apr
2003
8 Apr
'03
1:13 p.m.
Thanks for the info but I don't see the pads that you're talking about. Near
the center of the card are pads for a 14 pin DIP with nothing strapped. It's unlabeled
but is located between ICs 8D and 10D. Right next to the bracket on the very end of the
card is a place for an 8 pin DIP. It has the package outline painted on the board. But it
has two rows on header pins installed instead of a DIP package. (The rows are .4"
apart.) One row of pins is marked S1 and the other is marked 1, 2, 3, 4. There's
nothing jumpered on it either but I suspect that it's used to select the drive sizes.
Joe
At 02:49 PM 4/8/03 -0700, you wrote:
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.