Hitachi HDT721010SLA360 not spinning - TVSs OK

[bicubic]

Hello!

Yesterday I returned from a two week business trip and, when powering up my desktop PC, I found the HDD not being recognised. I instantly took it outside the PC and power it up again, and to my surprise it's not even trying to spin up.

The PC used to be on 24/7, with somewhat hot temperature (i.e. 110 F). Last time I turned off the PC for a week and then powered it up again, it needed a second chance to recognise the disk, but then it worked perfect. But this time it isn't even starting to spin. (I know, I should've made a backup THAT time, but it was the first time the disk showed a minimal strange behaviour)

The HDD is a:
Hitachi 1TB model HDT721010SLA360
P/N: 0A38016
MLC: BA3013
MAR-2009

I don't think it was a power failure as the PSU was plugged in but switched off (hardware switch on the back of PSU). I also measured the 5V and 12V TVS and they're not shorted. And with the HDD plugged and energized, they measure 5V and 12V across them.

I also tried to give a gentle hit on the sides, but nothing.

Is there anything else that I can measure or try before going for a PCB change?

Thank you very much and best regards!
JC

[poehere]

Most of the time on this it is Motor control chip or what you might call the big smooth chip on this one. If you swap pcb it will not help becasue Hitachi have NVRAM adaptive that have to be moved over before you can make the other board work. A simple board swap can not work for you on this one.

[bicubic]

Thank you for your response poehere,

What about a PCB swap and then transfer the old NVRAM chip to the new PCB? Does this usually work? (I would have to identify the NVRAM chip first)

Thanks,
JC

[poehere]

Yes find a good pcb that is the right one and transfer the chip across to the new pcb but first test the pcb it should at least spin up the HDD even if you do not transfer the chip across. If it spins it up then you need to move the adaptive to the new board.

[fzabkar]

There appears to be a 93Cxx device at location U5 in the following photo:
http://www.festplattenersatzteil.de/wp- ... 091839.jpg

AIUI, that's the "NVRAM".

[bicubic]

Thank you fzabkar and poehere.

Yes, that U5 is a 93C86WP, so that would be the one to swap! Thanks for pointing it. But I still need to find a donor PCB, and browsing the HDD Market forum I saw that they're hard to find and not cheap (plus shipping to Argentina).

So if anyone reading has one of these, please let me know and I'll send a PM.

Thanks again and best regards!
JC

[fzabkar]

If you could upload a photo of your PCB, I could help you test the onboard voltages. That may at least help you narrow down the fault.

Otherwise, if my abovementioned URL accurately represents your board, then there are four coils -- 2 x 2R2 and 2 x 100uH.

Measure the voltages at each of these coils with respect to SATA power ground.

Also carefully measure the voltages at each of the pins of transistor Q2 near the TVS diodes.

[bicubic]

Thank you very much! I'll be out until this weekend, but I'll test this values next Saturday and let you know the readings.

[bicubic]

Hello again fzabkar, and thanks for your help.

I made the measurements, and attached the image with the resulted voltages. Everything was tested with respect to the 0V point at the bottom. And the voltages tested at the power connector were:
+5: 5.11
+12: 12.17

Please let me know if you find anything suspicious!

Best regards,
JC

Attachments

PCB Measurements

[fzabkar]

Q2 is the +3.3V linear regulator for one of the Vio supplies.

L1 and L2 are part of the -5V Cuk converter for the preamp.

L310 provides the +2.5V Vio supply.

All appear to be working correctly.

L300 provides the Vcore supply for the MCU. I suspect that +1.1V is correct, but I can't be certain.

In short, I can't see any DIY solution.

[bicubic]

No problem, thank you very much for your kind attempt!

I think I'll take it to a DR to get a quote.. just hope they can make a full clone to a brand new HDD, that surely won't be a Hitachi!

Have a nice day,
JR.

[bboy_h]

No problem, thank you very much for your kind attempt!

I think I'll take it to a DR to get a quote.. just hope they can make a full clone to a brand new HDD, that surely won't be a Hitachi!

Have a nice day,
JR.

I have the exact same problem! Did you end up fixing the HDD?

[int0x13]

Hello, i have the exact same issue with my Hitachi HDT721010SLA360. Its not spinning at all, the TVS are all good (not shorted). I've measured a lot of voltage and resistance around the PCB. fzabkar can you help check if you see something suspect here?
I wonder what could prevent the motor to spin? I think the fault is on the PCB, because the VCM chip is probably not able to start the motor, but the question is why? I've read from member poehere that the Hitachi Deskstar HDD are prone to fault with the VCM chip. Is it a known issue? Where is exactly the issue? Inside the IC or outside on some other component?
The VCM chip is maked OA56511.
Thank you for any help.

Attachments

[fzabkar]

All the voltages appear OK.

Vcore = +1.085V
Vio1 = +3.3V
Vio2 = +2.5V
Vneg = -5V (preamp supply)
Vboost = 17V (charge pump for VCM and spindle motor)

I believe the SDRAM should normally run cool.

ISTM that the most expedient approach would be a PCB swap and NVRAM transfer. If you have some way of reading the NVRAM chip, then we could verify its checksum (XOR8 ?).

BTW, I don't have a datasheet for the motor + VCM combo chip. However, if you are interested in how these chips work, then see the following threads.

Tutorial - Linear and Switchmode Regulators used in HDDs:
http://www.alexsoft.org/viewtopic.php?f=59&t=231

Measuring VCM and Spindle Motor Current:
http://www.alexsoft.org/viewtopic.php?f=59&t=204

L7250, SMOOTH, spindle motor + VCM controller, ST Microelectronics:
http://datasheet.eeworld.com.cn/pdf/STM ... _L7250.pdf

Samsung ROM and Hitachi NVRAM CheckSum Calculator:
http://www.alexsoft.org/viewtopic.php?f=22&t=80

Fsum Frontend:
http://www.alexsoft.org/viewtopic.php?f=36&t=688

[int0x13]

ok I started to read your documents and there are very interesting. it is by far the deepest analysis of PCB Electronics I have ever read. Ive measured a voltage of 0.43v on pin a b c and common of motor pins and 1.9 ohms between phase to common pins and 3.6 ohms between phase to phase as expected based on your document. I think probably the motor driver chip is not sending the order to spin to the motor for some reason...
Maybe the feedback circuitry detects somethings wrong? Is there a test I can do to be sure its not the motor that is dead? Can I force some voltage using external PSU to start the motor? But I guess its not that simple because I'd have to generate a good pwm signal on the rights pins its not do-able?
I've tried to start the HDD with the paper under the head assembly contacts and its same.
About the nvram it is a microwire based chip a kind of spi I will try to dump it.

[fzabkar]

The motor controller gets its commands from the MCU via a 3-wire serial interface (data/clock/enable). This is described in the L7250 datasheet (it is not I2C).

It could be that the motor controller is faulty, or it could be that the MCU is dead, or perhaps the NVRAM is corrupt.

If you connect a serial TTL adapter to the pins at J6 (bottom left corner), do you see any diagnostic output? I'm just speculating that these may be RS232 Tx/Rx pins.

[int0x13]

I was doing voltage measure, maybe i did some short with probes or something (im not sure but i suppose it must be that) and then there is no more voltage on all coils except L3. After unplug and plug again the sata power connector, all the supplies are back.
I checked, J6 left pin is 3.3v and right pin is 0v. I will try to connect with TTL adapter to TX and RX and GND.

[fzabkar]

I checked, J6 left pin is 3.3v and right pin is 0v. I will try to connect with TTL adapter to TX and RX and GND.

Just for the moment, I would only connect the adapter's input pin. If you try to drive a PCB input pin with an inappropriate output voltage from your adapter, then you may cause problems. That said, I expect that the left pin would be the Tx output of the PCB.

[int0x13]

I tried a lot of combination but cannot get any terminal output.
I dont know the pinout, you say left pin is TX, so its connect to the adapter RX. What about the right pin which is 0v, it is ground? Also should i connect VCC?

[fzabkar]

I don't know anything about those two pins. All I know is that one of the DR tools comes with a Serial Command Transmitter box but the manual says that it has "no use at this moment".

Another tool makes use of terminal mode in some models. AIUI, ESC gets you into terminal mode, while Q quits terminal mode and returns to ATA mode.