Help me with ST4000LM024 ( Motor Conector Short )

[dumaster]

Hello friends of the HDDGuru forum, greetings to all !!!

I would like to know if any friend here on the forum has already encountered this problem, this ST4000LM024 after a few months of use stopped working, there is no clicking noise, but it has a continuous sound that gives the impression that the motor wants to spin but him can't!!!

I did the basics so far , I cleaned the 3 motor contacts both on the logic board and on the hdd case , I reassembled but the same thing continued , I made some measurements , one of them was measuring the motor coils , it seems to me a brushless motor in the triangle topology because it only has 3 terminals and the resistence gave exactly the same value of 2.0 ohms for de possibles combinations of mesurance, then i belive this motor is OK , then I went to measure on the logic board for try find something with problens of a short in the Driver IC of the Motor, to my surprise both measuring the resistance of 3 terminals of the connector on the Motor in relation to ground and measuring the resistance between the connector terminals all of them showed practically a short circuit (0.5 ohms)!!!

Could someone tell me if this is some peculiarity of this Driver Smooth by ST made for Seagate or if I really am facing a burnt IC ???

I would be very grateful for any help!!!

Follow photo below ( visually the Motor Driver CI has no signs of burning )

[fzabkar]

Are you sure that you don't have a stiction fault (heads stuck to platters), or heads jammed in the ramp?

The output stages of the motor controller have a pair of MOSFETs on each phase of the motor. These are connected as a half bridge. I expect that there would be residual charge on the MOSFET gates, and this would turn on the D-S channels. If you let the PCB sit for a while, the gate charges should bleed off and the phase resistances should then go open circuit (I would think).

[saltwater]

Hello friends of the HDDGuru forum, greetings to all !!!

I would like to know if any friend here on the forum has already encountered this problem, this ST4000LM024 after a few months of use stopped working, there is no clicking noise, but it has a continuous sound that gives the impression that the motor wants to spin but him can't!!!

I did the basics so far , I cleaned the 3 motor contacts both on the logic board and on the hdd case , I reassembled but the same thing continued , I made some measurements , one of them was measuring the motor coils , it seems to me a brushless motor in the triangle topology because it only has 3 terminals and the resistence gave exactly the same value of 2.0 ohms for de possibles combinations of mesurance, then i belive this motor is OK , then I went to measure on the logic board for try find something with problens of a short in the Driver IC of the Motor, to my surprise both measuring the resistance of 3 terminals of the connector on the Motor in relation to ground and measuring the resistance between the connector terminals all of them showed practically a short circuit (0.5 ohms)!!!

Could someone tell me if this is some peculiarity of this Driver Smooth by ST made for Seagate or if I really am facing a burnt IC ???

I would be very grateful for any help!!!

Follow photo below ( visually the Motor Driver CI has no signs of burning )

ST4000LM024 ( Board ).jpg

Hello!
Probably the HSA stucked on platter, and that's why the motor does not spins up.
No DIY soluton for this kind of problem, sorry.

[pepe]

Just measured a similar PCB and the motor contacts are shorted, the marked cap stores enough charge to keep the low side output transistor gates active, thus grounding the motor contacts. This is quite normal, your problem is probably stuck heads.

Attachments

[dumaster]

The output stages of the motor controller have a pair of MOSFETs on each phase of the motor. These are connected as a half bridge. I expect that there would be residual charge on the MOSFET gates, and this would turn on the D-S channels. If you let the PCB sit for a while, the gate charges should bleed off and the phase resistances should then go open circuit (I would think).

Hello friend, exactly that happened, I was measuring right after turning off the board, but even letting it rest for a few hours the mosfets were still connected, only after I went to each capacitor on the board and unloaded them did the motor connector pins rise the resistance above 100Kohms, so apparently the Driver is OK !!!

Are you sure that you don't have a stiction fault (heads stuck to platters), or heads jammed in the ramp?

Just for additional information this HDD stopped working while the computer was on, it wasn't during startup or during shutdown, in this situation is it possible for the heads to stick to the disks or get stuck on the ramp?

Is it possible to make some attempt to free the disks and heads ??? I have a backup of this HDD, there are only a few GBs that I would need to back up, I don't need to save all the content, which is approximately 2.5 TB, it's only about 10 to 20 GB !!!

[dumaster]

Just measured a similar PCB and the motor contacts are shorted, the marked cap stores enough charge to keep the low side output transistor gates active, thus grounding the motor contacts. This is quite normal, your problem is probably stuck heads.

That's what I mentioned to my friend just above, it was only after I manually discharged the capacitors that the resistance of the motor pins rose to acceptable values, thanks for the feedback!!!

About the head being stuck as I just asked the friend above, would it be possible to make some attempt to free the heads ??? As I said above, I have a backup of almost everything on this HDD, there are only a few Gigas that I would need to back up, it's only about 10 to 20 GB, I would be willing to take some risk because I imagine it would be very expensive to take it to a specialized company here in Brazil , everything here is very expensive !!!

Thanks !!!

[dumaster]

It would be very crazy to do the procedure that is explained in this video that I will leave the link below ???

I was also thinking of making a box to simulate a room with clean air, placing an inlet filter and a vacuum cleaner at the outlet on the other side of the box so that when the vacuum cleaner is turned on it can remove all the particles from inside the box and the filter does not would let new particles enter the box so it could create a safer environment to open the HDD!!!

What do you guys think of the idea ???

https://www.youtube.com/watch?v=F5Y7BniaRXg

[SWM]

Big difference between 250GB and 4TB...
And depending on how long the heads lie on the platters.
There is a high chance of a heads break.
Not to mention the dust.

[dumaster]

Big difference between 250GB and 4TB...
And depending on how long the heads lie on the platters.
There is a high chance of a heads break.
Not to mention the dust.

And what do I do, throw in the trash the HDD ???

Give me constructive, positive, cool suggestions and not just arguments to discourage me...

Thanks

[Lardman]

Give me constructive, positive, cool suggestions and not just arguments to discourage me...

No one here will encourage you to destroy your drive. That video is click bait and responsible for destroying so many drives. The time when you could manually yank the heads from a platter and expect them to still work are long gone. If you want to try it, that's up to you but don't expect us to tell you it's a good idea or even that it will work, as it isn't and it wont.

If the heads are stuck to the platters you can buy the correct tools to lift them off (try apextool labs) but you'll likely need to replace them as they'll be damaged.

[SWM]

If the engine jams in your car, will you also do it through the forum?
Even if the head mount is bent by a fraction of a micrometer, it will turn your data into magnetic dust when it starts up.
You can even take a video. Then connect a similar working disk and say that everything is OK.

[dumaster]

Thanks for the feedback, now you've two given me more details if I try to do it like in the video and that has a high probability of damaging the heads if they aren't already damaged, I really appreciate the information, I know you're two giving a warning but the information is really sad and disheartening !!!

Now I ask, if the platters ( I believe there are two platters in this model ) were spinning when the problem occurred and there was no power outage, is there any chance of it being the logic board? would it be possible for me to rotate this motor with some DIY circuit just to know if this motor is OK? because if the motor turns OK it is because the logic board has a problem, am I not correct in my reasoning?

Many thanks @Lardman and @SWM so far for the advice and information !!!

[SWM]

Buy a pair of donors. Check the electronic board on one. Practice getting heads out. After examination under a microscope.
Oh yes, also a microscope, a clean box, equipment, programs ...

[pepe]

ouch, i just saw my prev answer was already outlined by fzabkar, sorry.
Now this model has 8 heads, 4 platters. You have very slim chance to get it working with new heads and without the proper equipment. On the other hand, you have a really good chance of making the situation much worse as the new heads will likely not write the service area (SA) correctly and screw up critical but at the least some info essential for the unit to properly initialize.
Even some labs have no way of preventing this, i'm just having one that became unable to start after head swap.
So it might be tricky even with the right tools.

pepe