In message , cameo
writes:
On 4/25/2015 11:50 AM, Gene E. Bloch wrote:

Don't yuo just love that

I have had drives that had been idle for a long time not spin, but I was
able to start them (more than one drive, over time) by mechanical shock.
[]
These are methods of desperation, but you could tell that...

I don't think such drastic measures will do me any good if the real
reason is a fried IC board due to an incorrect pinout of that 4-pin
alternate power supply I boughth on ebay and I returned already.

I did some Voltage measurements on this NewerTechnology Universal
adapter and here is what I got on the 4-prong molex connector on both
the 5V and 12 V prongs:

Without connecting it to the HD (no power load):

5.12V and 12.38V

I'd say acceptable, though a bit high.

After connecting the power supply to the HD:

4.73V and 13.57V, respectively.

Hmm. Most TTL ICs used to be specified to work over 5 ±¼V; the CMOS
equivalents are usually tolerant of a broader range. I'd have said that
that probably _would_ still work (though that's at the connector; could
be lower at the actual ICs).

This doesn't make sense. The 12V pin's voltage should also drop under
load, not just the 5V pin's. Even the 5V pin voltage seems to drop too
much IMHO, especially since there is no USB load on it. I assume the
12V is used to spin the HD platters.

That's the usual assumption. Although that's very high, I would _hope_
it hadn't fried anything.
[]
Next, I think, I'll try to see if I could remove the IC board to see
the component side of it if there is some visible scorching on a
component. I would have done it already if I had the right size torx

A lot of these boards have a surge-suppression device across the supply
line, which rumour has it can fail short (possibly without any visible
sign); I'm not convinced, but if it has, it'd stop the power reaching,
and unsoldering one end is not that difficult. But if that's the case,
the voltage should almost disappear under load ...

If you put your ear very close to the drive when you apply power, can
you hear _anything_? With mine where the head was stuck to the surface,
I heard a little tinkling or ticking - I presume that was the head
swinging mechanism trying to move.

screw driver the board is attached to the HD body. Then I might also
visit some eRecycling stores to find the exact same WD HD and
cannibalize it for its circuit board. Fortunately this seems to be a
fairly ubiquitous HD about 10-12 years ago. So maybe I get lucky.
Looks like a fun project, doesn't it? ;-)

Yes. Are you planning to continue to use the drive, or just intending to
rescue the data on it? If it comes to opening it, unless you've got a
_phenomenally_ clean room, I'd stick with the latter; if replacing the
board works, you _might_ be OK, though unless it's a particularly
expensive drive, I'd probably still not trust it.

--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Dictionary: Opinion presented as truth in alphabetical order. -John Ralston
Saul, essayist, novelist, and critic (1947- )