On 22/02/2010 20:33, Tony Duell wrote:
Another issue sprints to mind. The termination
resisotr pack in the
drive terminated/pulled up the signals from the controller to the drive
only. The signals from drive to controller were terminated by 150 ohm
rsistors on the cotnroller PCB. So the drive outputs have to be able to
sink 33mA too. I know that the full-height Sony 3.5" drives used 7438s to
drive these lines, and coule sink that current. What about more modern
drives? Is there a problem with linking those to a 'classic' controller
board?
We used to see problems on Acorn Archimedes machines, which had internal
modern-style 3.5" drives and LS TTL drivers. Adding a normal 5.25"
drive often didn't work because there was not enough drive current.
However, changing the LS TTL for standard TTL fixed that, and the
internal 3.5" still worked fine.
--
Pete Peter Turnbull
Network Manager
University of York