8 Dec
2006
8 Dec
'06
5:19 p.m.
The SA4000 that I have a techincal manual for (and
which is used in the
PERQ 1) uses a stepper motor to move the heads. It doesn't (AFAIK)
require any feedback signal from the platters to go ready...
No, I was wrong. According to the manual, the 'ready' signal depends on a
clock signal that comes from a special track on one of the platters,
picked up by a fixed head. The basic procedure if the drive won't go
ready is to look at the output of this head's amplifier, if that's
missing/incorrect to troubleshoot or replace the read/write PCB (and if
that doesn't get it back, then the fault is inside the HDA and is not
field repairable). If the output of the clock head amplifier is OK, then
therer's a fault on the control PCB.
I can find more details if you want.
-tony