14 Jan
2004
14 Jan
'04
7:31 p.m.
if the 7900's run like the dynex 6000's and microdata 9000's then there is a
closed loop servo system that does a load command and sets the servo
to stop when the load position is hit on the reticule. When one seeks,
there is a difference sent to the servo, either + or - in track number, and
the servo is allowed to slew until the number of tracks pass thru the
reticule.
If you unplug the servo coil, then the above drives are perfectly
happy to let the potential set on the open connecter (molex also in
above). and wait for the load ramp.
We could load the heads manually, and move them around to do
alignment tests as well. It was really nerve racking to load the heads
and unload them though, as you really didn't want to pause at the
load and unload point or the heads would make really bad noises.
Jim
Jay West wrote:
Isn't
there some way to disable the positioner drive (either by pulling a
plug, pulling a PCB, or an internal switch)? The RK05 has a switch on the
servo power amplifier for this, for example.
If you can disable the positioner (and if the drive logic doesn't care!),
you can then run the blower for half an hour or so without the heads
trying to load.
There is definitely a way to do this. I forgot what it is! I seem to recall
it's a molex connector you just leave open. I'll have to look at my 7900
later.
Jay