11 Apr
2006
11 Apr
'06
2:54 p.m.
Tony Duell wrote:
Yes, I left the motor, cam, and switch. I just removed the actual brush
arm from the shaft, leaving everything else so that the logic would
'think' the brush is still in place.
Sorry if some of my questions were 'going over the bleeding obvious'...
All too often I've found I've made assumptions about what the other chap
has or has not done, and wasted a lot of time going along the wrong path.
for power
supply checkout, I went ahead and removed the brush assemblies.
What did you remoce? Just the brush tips? Did you leave the motor, the
microswitch, and the operating cam? Without those, you might have
problems getting the drive to go ready.
It's
possible, but unlikely. I suppose you could start by looking at the
output of the sector transducer (posibly after the amplifier circuit).
That's what the drive uses as a speed reference anyway (the motor in the
RL is not locked to the mains, unlike most other demountable hard drives,
there is no change for 50/60Hz). See if the signal is stable and has the
right frequency (compare it with the same signal in another working drive).
Excellent advice. I will try this. I do have a scope, though I'm more
of a software geek rather than a hardware engineer!
:) I just find it
interesting that both of these drives (the 'dirty' set) exhibit the same
behavior vs. the 'clean' set, when all else is the same, i.e.,
controller, etc. I may be fixating on the noise as the cause of no
READY indication, but maybe it's something else.
Another 'obvious' question : You have made sure the head lock is not
fitted on the 'dirty drives'? That would stop it going ready.
I'll begin here, and see if this resolves the
noises I'm hearing. I
still hope that IF the lubrication helps to steady the RPM, it might let
the drives go READY.
I think there's some kind of grounding brush on the spindle, visible
under the little cover on the bottom of the drive. That can, I suspect,
make odd noises, but it shouldn't stop the thing going ready.
No, you can
remove and replace the spindle without upseting the heads. In
any case, the RL drive has an embedded servo burst in each sector header,
so head alignemnt is quite easy (you need a 'scope, but no special
alignment disk, any normal disk will do).
I was just worried that there might be some vertical alignment issues if
the spindle assembly wasn't put back correctly. I have no idea if there
are shimming or 'leveling' screws that would assist in making sure that the platter is aligned vertically (along its axis) so
that the heads
have the proper 'flying height' for both surfaces of the platter.
-tony