hdd won't spin, no clicks, diode ok?

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jonnietheyorkshireman

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Sep 9, 2013
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My samsung np300e5a laptop wouldn't start after having shut down normally a day or so earlier. The fan starts to spin but then the thing shuts down, no beeps. After some investigation I connected the hdd (samsung HN-M750MBB/SCC) via an external hdd adaptor to a USB supply. The motor doesn't spin. The LED goes bright, dims then goes bright again. There are no noises from the motor, no ticking or clicks. The only diode I can see on the pcb is marked ZA and when the PCB is plugged to the USB supply I can measure 4.5V across it which would seem to suggest that the diode is ok. Has anyone any suggestions as to what I should look for now? There are no signs of damage to the pcb when viewed through a 10x microscope. cheers. Jonnie
 
Solution
F
Does the laptop still shut down in the same way after removing the drive?

As for your motor measurements, they appear to be OK. The motor has 3 phases plus a common terminal. The phase-to-common resistance would represent the resistance of a single phase, which is 2 ohms. The phase-to-phase resistance would be twice that, namely 4 ohms.

You can see a typical arrangement in the following article.

Measuring VCM and Spindle Motor Current:
http://malthus.zapto.org/viewtopic.php?f=59&t=204&p=1365

I notice that you mention a jumper. I tried to determine what this jumper does, but the product manual only states that it is for factory use. Have you tried removing it?

Samsung SpinPoint M8 Product Manual...
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F

fzabkar

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Sep 22, 2010
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AIUI, if it's a PCB fault, and if you need to replace the board, then you will need to transfer an 8-pin serial flash memory chip, or its contents, from patient to donor.

If this is your board ...

http://farm9.staticflickr.com/8361/8435666434_da5f1b82d4_h.jpg

... then the relevant chip is at the RH edge of the PCB, below the Marvell MCU. This chip probably has a metal base, so desoldering it would be difficult. Some PCB suppliers offer a free firmware transfer service.

If you wish to perform some voltage measurements, then please upload a photo of your board.
 
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jonnietheyorkshireman

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Hi
The measured voltages and resistances are on the attached picture - I'm afraid the multimeter I've used is autoranging so all the resistances are high.
http://www.flickr.com/photos/101556998@N07/9717124260/
The resistance between all of the coils and ground are the same at 8.6Mohms.
Th IC above the coil has N332 and 5172 on it.
Hope these are useful.
cheers
jonnie
 
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fzabkar

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"ZA" is the 5V TVS diode. It must be OK, otherwise the board wouldn't be getting any power.

The +2.5V supply is the Vio voltage for the MCU, SDRAM, and flash memory.

The +1.0V supply is the Vcore for the MCU. Both are OK.

The "N332 5172" device appears to be a PWM controller, but I don't recognise the markings.

Initially I thought that the drive may have had a "dynamic" short circuit. That is, the drive appears to overload the external supply only after it attempts to spin up. A USB 2.0 port can sometimes produce this symptom. This is because the port is current limited to 500mA, whereas a 2.5" drive typically draws 1A at spin-up. However, your laptop is also producing the symptom of an overloaded supply, namely a kick of the fan and then shutdown.

I don't know where to go from here. I'm assuming that you have confirmed that the laptop fault was definitely caused by the HDD, and not just a coincidence. One more thing you could do would be to measure the resistances between each pair of terminals on the motor.
 
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jonnietheyorkshireman

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Hi
Thanks again for your time.
The motor has 4 wires giving 6 possible measurements - 3 are at 4ohms and 3 at 2ohms which seems ok to me.
I could try a scope on the motor driver outputs but I'm not sure where to go from there.
My diagnosis of HDD failure followed from wanting to get something off the drive - I put it into an external housing (complete with jumper) and it did nothing - as it had in the Laptop. Perhaps I should try connecting the hard drive that was in the external housing into the Laptop to see if it spins up - or is there a risk of damaging it that way?
I do appreciate your advice.
cheers
jonnie
 
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fzabkar

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Sep 22, 2010
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Does the laptop still shut down in the same way after removing the drive?

As for your motor measurements, they appear to be OK. The motor has 3 phases plus a common terminal. The phase-to-common resistance would represent the resistance of a single phase, which is 2 ohms. The phase-to-phase resistance would be twice that, namely 4 ohms.

You can see a typical arrangement in the following article.

Measuring VCM and Spindle Motor Current:
http://malthus.zapto.org/viewtopic.php?f=59&t=204&p=1365

I notice that you mention a jumper. I tried to determine what this jumper does, but the product manual only states that it is for factory use. Have you tried removing it?

Samsung SpinPoint M8 Product Manual:
http://www.seagate.com/files/www-content/support-content/internal-products/spinpoint-m-series/en-us/100698035h.pdf
 
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jonnietheyorkshireman

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Sir, you are a genius.

With the HDD removed the Laptop still shuts down in the same way. So the fault lies elsewhere.

And the reason the HDD doesn't spin up is that I'd slavishly transferred the jumper from the WD3200BEVT external HDD to the samsung one from the Laptop along with the USB adapter from the enclosure. A bit of research shows that the jumper on the WD HDD is to enable RPS (reduced power spinup). I removed the jumper from the HN-M750 and hey presto! it spins and I can access all my files again.

Now I just need to work out what's wrong with the Laptop.........

Thankyou for your help - as they say: a little knowledge is a dangerous thing. Now where did I put that hammer?
 
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fzabkar

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Perhaps you have inadvertently found a Power Up In Standby (PUIS) jumper? I'll have to research this with the data recovery people. AIUI, two of those jumper pins are the Tx/Rx signals for the serial diagnostic console.

As for the laptop, try to locate the power supply pins and test them for shorts to ground.

FYI, this site appears to be a good source of schematics (it's in Vietnamese, though):

http://kythuatvitinh.vn/forumdisplay.php?39-SamSung-Schematics-(122)VSa
 
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fzabkar

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I'm in Australia and I'm a retired electrical engineer with experience in electronics.

I participate in various technical forums to keep my brain from going stale. Data recovery is particularly challenging because just about every little snippet of information, no matter how trivial, is treated like it were an industry busting trade secret.

One more resource that you might find helpful, in the event that your laptop's PSU is the actual culprit, is http://www.badcaps.net/forum/

Best of luck.
 
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jonnietheyorkshireman

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Hi again
I've been building up the courage (and gaining a little understanding) before searching for a short on the motherboard.
There are 3 coils marked R39 next to the cpu ( an i5 sr04w). These measure roughly 10 ohms to ground with the cpu fitted. If I remove the cpu from its holder the resistances between the coils to ground are roughly 6Mohms. Is this normal or does it suggest the cpu has failed? The thermal paste was grey and pretty hard.
Have you any thoughts?
Thanks
Jonnie
 
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fzabkar

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I checked the Vcore resistance on an old desktop motherboard. It measured 4 ohms, so I don't think yours is unusual. In fact, when the CPU is working at full power, it may dissipate as much as 100W. Vcore would be typically around 1V, so this would correspond to a resistance of around 10 milliohm. Even at 10W the resistance would be 0.1 ohm. Therefore a static resistance measurement probably isn't very useful, unless it is a dead short.

I would identify all the coils and chip inductors. These would be the landmarks that define the onboard switchmode DC-DC converters. There should be a PWM controller IC nearby.

For example, one of the larger coils would identify the +5V supply for the HDD.
 
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