11 Apr
2006
11 Apr
'06
12:41 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.
Yes, indeed, I'm using the same platform for my testing of all drives --
both the dirty drives that are 'broken', and the clean set that work --
with every other component except the drive being the same. That is,
I'm using the same 11/23, RLV11 controller, cables, terminator, etc.
I'm just swapping the drives themselves.
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.
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.
Fortunately, the 'clean' set of drives are now fully functional, having
been tested
with one of the 11/23s.
Unfortunately, after mounting and LOADing a known good disk cartridge,
neither drive
from the 'dirty' set will show READY after spinup. Though the details
You do have these cabled to a working controller, I trust? You need the
clock signal from the cotnroller for the drive to spin up and go ready.
I wonder if dragging bearings are preventing
the drive from
becoming READY due to uneven RPM?
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).
I would not try to lubricate the spindle bearings. You'll never get it
apart anyway (t's pressed together, and you have to maintain mecahnical
balance, etc. There may be a ferrofluid seal in there too). The risk of
contamination to the disk/heads is too great.
Hmm...okay. I'll let this go for now, hoping that the issue is with
the motor.
It shouldn't hurt to take the spindle motor out,
take it apart (obvious
through-bolts) and oil the bearings. I think they're phosphor-bronze
bushes, not ball races, in which case you want a medium machine oil on them.
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.
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.
Many thanks, Tony, for you suggestions. I'll let you know how it goes,
probably later in the week. I've gotta satisfy the tax man first!
April 17 is fast approaching! :)
J.