recently my hdd: Maxtor diamondmax 21 (STM3500630As), was behaving in a strange kind of way..
the problem is, that the hdd cannot get it to power up and spin correctly unless I keep unplugging/replugging its power cable many times, until I hear it spin correctly...
2 days ago, I tried to power it up, and it didn't power up at all!!, I don't hear it spin,... nothing!!..
also at the back (the pcb board) i noticed that the area around where the power plug is plugged, gets very hot!..

so what could be the problem ?
is there is any chance i could get it to power up so i can back it up?
thanks.

1. How about power supply?
2. Do you try connect disk to other computer?

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Flash Killer - everyday new resources (pinout, XOR, ECC,config) for flash devices

Do you have a multimeter?

Can you upload a photo?

you see, I was using the hdd externally via a sata-to-usb adaptor, which comes with its power supply.
the thing is that when the hdd was working, it used to make soft clicking sounds without spinning up correctly every time i put the power cable in. until after a number of unplugging/replugging of the power cable, it spins up fine.
now, it does not even make the soft clicking sounds when I put the power cable in anymore!.

Yes I have a multimeter.
and here is a photo attached.

Some of those power supplies are hopelessly noisy and [for some drives] can't supply enough startup current on the 12v line.
Have you tried connecting it to a good pc psu? I'd also give the hdd connectors a clean with some contact cleaner, they look a little grotty and may be the cause of the heat [resistance + current = heat]

That vertical cro scaling is right folks - 2v per division. The drive had no chance of running properly!!

I will try your suggestion and report back.
by the way, the heat i get not on the plugs, the PCB board is the one that gets hot ( the area under the power socket) after plugging the hdd to the power

Set your meter to the 200 ohms range and measure the resistances of the two TVS diodes in the photo:
http://www.users.on.net/~fzabkar/temp/S ... AS_TVS.jpg

They should not measure 0 ohms.

Ok, I made some test, but not sure if my multimeter is behaving correctly, or did I measure right.
here is what I did.
-I set the multimeter at 200 ohms ( and without touching anything, it gives me on the screen the digit: "1" )
-I started measuring every diode by placing the probes on its sides.
-the right diode (on the screenshot) gave me about 20 ohms (also gave me a beep in the continuity test)
-the left diode gave me 1 ! ,.. also continuity test didn't give me a beep!,... does that mean its the culprit ?!

Ok, I made some test, but not sure if my multimeter is behaving correctly, or did I measure right.
here is what I did.
-I set the multimeter at 200 ohms ( and without touching anything, it gives me on the screen the digit: "1" )
-I started measuring every diode by placing the probes on its sides.
-the right diode (on the screenshot) gave me about 20 ohms (also gave me a beep in the continuity test)
-the left diode gave me 1 ! ,.. also continuity test didn't give me a beep!,... does that mean its the culprit ?!

Other way round, left is good, right is bad. These are transient suppressor diodes connected in reverse polarity with the rails to ground.
Seems you need a 5 volt tvs of another board. You can also buy them.

Technically, you could just disconnect it and run the drive without it, but you would want to make sure you only connected the drive to a good, stable, well filtered and trusted power supply, and then only for the purpose of recovering the data.
Fitting another tvs is the safest way to go. Make sure you connect it the right way round.

thats strange!
I desoldered the left one, but this time I connected the hdd to the pc power supply and the hdd worked!!
so how it could be the other way around pixels ?!

If you still have the diode that you removed, measure it again.

it gives me 1 (as if it measures nothing, cause my multimeter gives "1" without measuring anything)

That's telling you that it is overrange on that scale. If you switch to the diode range, then it should measure overrange in one direction and about 600 in the other direction.

In short, I think the diode is good and there is an intermittent fault elsewhere on your drive.

you're right, I got the exact measurements you gave me.
but this leaves me with a puzzle!
why the other TVS gives me a continuity?!
and how the hdd worked ?!

The 5V TVS diode is connected across the +5V supply. Therefore you are not just measuring the resistance of the diode, but everything else connected across the same supply. A resistance of 20 ohms is low, but at 5V it only represents a current draw of 0.25A.

Yes, measuring devices in-circuit can have it's hazards.
I can only assume that the 12v tvs is suspect and is going into avalanche and drawing current prematurely.

that means ?

A tvs is like a pressure relief valve. When the pressure becomes too high, the valve is pushed open. When the pressure drops, the valve closes again.
With the tvs, when the line voltage [pressure] reaches the voltage rating of the tvs [the spring tension in the valve], it very quickly begins to conduct current [the valve opens] to prevent the voltage going any higher.

It seems your 12 volt tvs may have a 'weakened spring' and is 'opening' too early

Ok, I get it now,..
I will see what I can do.
but anyway, I am very thankful for all of you that have helped me here..
You're the best guys...
thanks..