niddo wrote:
Hi Old Tech
We use Isopropyl Alcohol to clean head sliders, I seem to remember some paper I read about the lubricant used on platter surfaces being particularly sensitive to most solvents, I think this may cause more problems than it solves.
Thanks for info, niddo. Maybe I have it wrong. Do the modern heads slide on the surface like the floppy drives? I assumed it was still air pressure holding them up. There appears to be a lubricant on the surface of the platters. I don't have a professional clean room and I got a speck of dust on the surface that would not blow off. I used isopropyl alcohol and it left a residue that did came off with a soft material.
niddo wrote:
From experience the platter in an old style Maxtor is normally fine, clicking is almost always a fault within the head assembly itself.
If you are prepared to try I would suggest sourcing an identical drive and conducting a head change, this is very difficult without special equipment, at least in cases where there are 4 or more heads, normally a head change comb or some kind of platter mounted head seperators would allow you to safely remove the heads from the outer platter edge.
Right now, I am taking my time, and I will only try a head change as a last resort. I want to be sure the preamp is working first and I need to finish tracing the circuit. I have not run the drive since the clicking started. I am looking at a way to disable the voice coil mechanism so I can power up the drive without the heads seeking. Unfortunately, the spindle motor seems to use a sensing circuit which checks for the magnetic field on the motor itself.
For that reason, I don't want to power up the board without it being attached to the spindle motor. Without a load, the board will probably shut down, but worse still, I might blow something running it with no motor load. I thought about using resistors as a load, but if the circuit is testing for the back EMF produced by the motor magnetic field, that wont work.
niddo wrote:
Alignment issues will lead the drive to click away and not do an awful lot else so be extremely careful when mounting the new heads, they have a tendency to come together making it very difficult to seperate them and get them on the outer edge of the platter.
thanks for that advice. I have read Stanislav's article and he used flattened plastic straws, which I thought was a brilliant idea. When I worked on drives, long ago, they used an oscilloscope to read a pattern on the drive. The modern drives seems to align themselves. Is that right?
The reason I don't think it is a mechanical failure on the heads is that the original problem began after a power failure. I am attempting this data recovery for a family member and they had the AC power running straight off a wall outlet rather than through a surge protector. The plug was accidently pulled, and that's when the problems began.
There's a possibility that the drive wrote to the disk while it's logic was out of kilter. Then again, the drive worked for a while afterwards but it was very slow and Windows was having trouble reading. It was reporting an inability to read certain files that were there. Also, it reported difficulty with different files each time.
niddo wrote:
Just my thoughts on it, my advice; if you have done head changes before and are confident in your abilities (and have access to the correct spare) then go for it, its the only way to learn, we all started somewhere, normally with a few damaged drives under our belts before we achieve any level of success
When I say that I did head changes, it was many years ago on much smaller drives. Still, the head mechanism was under considerable pressure and it was nearly impossible to pry the heads apart with one's fingernails. Also, the heads were rounded and did not sit on the disk surface. They were activated from a linear motor and loaded when required.
I appreciate your encouragement and I'm looking forward to trying. If I did not have data to be recovered, I'd be a little more reckless.
After your advice, and reading Stanislav's article, I feel confident in my skills as far as attempting it.
As I said, I don't have a professional clean room. I need to work in my home on a table. I'm looking into ways to build a small tent over the table using plastic sheets and using a hepafilter to control the dust. Of course, I'll use a mask, gloves and hair cover, like a surgeon.
With respect to alignment, do you know if it's possible to remove the platters?