Such can often be the case! Often to the contrators it's "just
a job" and they're interested in finishing as soon as possible.
Yeah, tho in this particular case its just a different philosophy.
What you're supposed to do is use things called bar chairs
which are a little 4 legged thing that sits on the membrane
which the reinforcing mesh sits on, which places the mesh
at the right level in the concrete slab.
The pros dont bother with those, they have the mesh
flat on the membrane, at what would be the bottom
of the concrete slab and lift the mesh up with a hook
thing when the concrete is being poured.
The problem with that approach is that it depends on the
individual to lift the mesh to the right level in the concrete and
its a lot more reliable to use bar chairs instead as far as
getting the mesh at the right level in the concrete is concerned.
They're just a nuisance to use, each one has to be placed
and attached to the mesh with a wire twist thing. Much
quicker to just lift the mesh as the slab is poured.
However a savvy homeowner (with a nack) will often do
better because they take the time and care to do it right.
True. My next door neighbour had his house professionally
built and the stupid kid doing the cleanup in the bathroom area
thought the floor drain was a great place to sweep the rubble |-)
Well, sadly, most people DON'T have
such a nack! Funny story. Broom. Heh.
Yeah, I did have real reservations about that one doing
anything. Fortunately it all worked out pretty well.
Plenty of my neighbours cant even
fix their lawnmowers or kids bikes.
That's the way to do it. Now, I just wish I could look
over the shoulder of data recovery people as easily!
Yeah. I also owned a light plane at one time, with some other
people, one of which had worked for the local aircraft maintenance
operation, so we did all that work ourselves as well.
He's in a different class altogether, quite capable of
making sophisticated firearms from metal bar stock.
Interestingly he is hopeless at anything electronic
tho, even tho his father was heavily involved in that
commercially. He doesnt seem to be able to handle
things where he cant see whats going on very well at all.
Indeed. Since few people wish to engage in it correctly, you
see few sources for info. Then you have the few firms who
exist to serve the big money firms who foolishly have tens of
thousands of $ worth of data on hard drives without backups.
Yeah, there will always be that market, enough stupids around.
Those firms aren't going to be forthcomig
insofar as putting up tricks of the trade.
Not a lot of point really, most of what they do cant
be done by someone after just reading about it.
Well, SOME of the steps are simple and obvious.
However, if those things fail, then workarounds are
incredibly valuable. Sometimes with such things there
can be little gems of tricks that could help revive the
drive without having to go into the enclosure.
In fact thats something that is pretty desirable, discouraging
people from doing that unless its been proven to be necessary.
As for my "no-spinup" drive, I'm hoping the PCB will do the trick (not
much I can do until I find a used one of the same series on eBay).
And maybe not even then. Someone did try that with that drive model
and the drive appears to not allow a simple logic card swap. Havent
tried that myself by swapping between two known good drives tho.
The problem may just be between two particular microcode rev levels.
The other drive may force my hand with the opening of the enclosure
I think from the symptoms that its unlikely to be useful. Its
much more likely to be a dead transistor on the logic card
thats stopping the rotation motor from spinning the drive up.
Its obviously possible to move transistors from the good
logic card to the bad one if you can do that sort of thing
and its pretty routine to work out which have died too.
(only because the problems are indicating that it may
be the ONLY way to get the data, in which case a time
will come when there's nothing left to lose by trying).
Of course, I could have been bald already
If any of these components is on the PCB,
They all are.
then at least there's an external option.
Not sure what you mean there.
Indeed. However, the procurement of a similar drive is the next
step, since if the PCB transplant doesn't work, then the PCB
may be the 'donor' for whatever parts may become necessary.
Precisely.
98% sure that's not the problem here since the platter seems
to move a bit. It's almost surely in the motor or motor control.
Yeah, and motors dont fail all that often.
If I'm lucky, it will be in the motor control.
If I'm not lucky, the motor will be the problem
and it will not be able to be manually spun up.
If the motor has failed, it would normally be a winding and
that doesnt prevent the motor from being manually spun up.
Non trivial spinning it at the speed accuracy that necessary tho.
Well, the drive I've been discussing which won't spin up is the 40gb
drive. The other drive is an 80gb drive that failed to be recognized
only a week after purchase. It passed diags and formatted just fine.
Then 3 days after putting data on it, it just one day failed to be
recognized by the computer when I tried to access the drive.
The 80gb drive seems to have some odd data intermittency problem.
Sometimes it will appear to the controller, but 9/10 times not. When
it DOES appear, it won't continute to be accessible.
Same happens on different computers and different
controller boards. Same happens whether the system
is powered down or just reset. The data timing out means
I can't read data from it before timeouts occur. I swapped
out the PCB on it and the drive STILL behaved the same
(although the PCB on the failed drive worked just fine on the new drive).
So it's definitely NOT the PCB since the beahaviour was the same.
Weird. Exactly which drive ?
It isnt a Maxtor ? Some of those can produce a result like
that. The problem appears to be that they load at least
some of the code off the platters and when that doesnt
succeed, they dont even report the model number correctly.
If thats the case, it may well be a crack in the flexible cable
to the heads that prevents the data being read all the time.
This is more of a pickle of a problem since
it spins up but won't supply data properly.
Those sometimes can have the data recovered by putting the
drive in a plastic bag in the freezer and getting the data off
before it warms up too much. Best to do that in a dry environment
tho, otherwise you can get condensation forming on the drive.
The cold basically changes the mechanical detail in
the flexible cable and can be enough to conduct for
a while, across the crack in the metallic trace.
Anyway... as a footnote to the whole "drive repair" scenario, I got
to dissect a similar dead hard drive to learn how it goes together.
It was actually a lot more mecanically simple than I expected.
Yeah, very simple and elegant designs now.
Nonetheless it's amazingly delicate with obviously any
number of things which could go wrong trying to work on it.
And if you calculate the track spacing, you're amazed that they can ever work.
Since I was able to dissect the drive, I get the feeling the 80gb drive has
a failure in the head assembly, the chip attached to it or the ribbon cable.
Most likely the flexible cable to the heads.
Could be a bad joint with the head preamp tho.
At any rate, this is all ONE factory assembly that cannot really be worked
on easily. Being that the logic board (PCB) was not the problem, the only
other path of data is this assembly. It very well may be I will have to swap
it out with a good one to have any chance of success - a daunting prospect
to accomplish without contaminating the platters
Its not all that hard to open without contaminating the platters.
Its very non trivial to try moving stuff inside there between
drives, particularly aligning it in the new location.
or mashing the replacement head assembly
(which is like juggling eggs to work on, I can tell).
The only other hope with the 80gb drive is to find some currently
unknown WORKAROUND which somehow could "juice" the drive
into giving up its data. This would require HEARING about sich
a 'fix' from someone who has encountered the problem before.
The freezing is worth trying. It has worked for some.
As for the 40gb drive... I also learned that there really
aren't too many components affecting the motor.
Correct.
Barring a 'stiction' problem (which is 98% ruled out),
the PCB is the only other component driving it.
Correct.
If the PCB isn't the problem, then it comes down to two possibilities:
1. Finding a workaround to jump start the motor, such as a hotwire job
Not possible with the sort of stepper motor used as rotation motors.
or manually spinning the platters fast enough or
Its not so much fast enough as at the right speed.
And since the heads fly on the platter surface, it isnt hard
to produce head crashes if you stuff up the manual spin up.
2. Replacing the motor... which, while mechanically a very
simple prospect, is a LAST resort, since it requires pulling off
the individual platters and then replacing the motor which only
invites any number of chances for contaminating the platters
The problem is aligning them again. The track were
written on the platters after the drive was assembled.
(and then the new motor may have timing difference which
may STILL cause it not to allow me to read the data).
Thats shouldnt be a problem. Alignment would be tho.
It all boils down to learning as many potential workarounds
as possible before trying some of the last-ditch efforts.
True.
