Hi there,

I just got this drive on my table, not spinning up at all. I'll have to do further checks tomorrow but wanted to ask first whether there is a known problem with this series causing no startup. It's the pcb version with the flash integrated in the MCU (U7 place empty).

What I've checked so far are the internal power supplies (2,5V 1,2V negative supply for analog chain) which are all up.
The crystal on the MCU show no oscillation at all, another Hitachi drive with a similar yet not identical pcb shows a clean 0,8Vss sine wave on the osc output of the MCU.
I wonder if the MCU knows a sleep mode with the oscillator shut down?

Hi Shaun,

As much i know its a general problem and can be happen with any hard drive. I would like to suggest you that please check your connection properly one more time.

@Aldis Wilson:

Which connection are you suggesting that shaun checks? Your post didn't say...

I am suggesting him to check his drive connection........ and to check drive on other system as well.......

Thanks for your reply, but it doesn't answer my question


But which drive connection? Your comment is too vague to be helpful

And how would (whichever connection you are talking about) having a problem, explain the specific voltage & oscillator measurements which shaun has described?

Unfortunately IMHO, I don't find your comments to be useful - perhaps if you give more details of exactly which connection could be wrong, and how that would explain all of the symptoms described by shaun, then we can learn something from you? Or, perhaps, you don't understand what those measurements from shaun actually mean?

Hi there,

hadn't much time today, but either the MCU is dead, in an unknown sleep state or the Vcore for the MCU is below limits.
I've measured 1.1 volts, a similar but not identical PCB on a HDP725050 has 1.3 volts. This may be a problem, or pretty fine.
When I feed a 50MHz signal into the OSC IN pin with the crystal removed, the OSC OUT will not show the inverted version of my signal - which may also be fine if the oscillator circuit in the chip is different from the usual inverter design.

Does anyone know what to watch out for pcb swapping? The MCU has integrated flash, but an external EEPROM which I assume holds the adaptive data.

I don't have either of those drives available in my (non-DR) job, but if I was in your situation, I'd compare the MPU types on those 2 boards. If it's the same MPU on both, then the different measured Vcore voltages would be a concern.

Just a thought...

What are the first two lines on the little white sticker on the PCB?

_________________
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If the Vcore supply were too low, wouldn't the power supply monitor circuitry within the motor controller sense this condition, and wouldn't it then negate the Power On Reset signal to the MCU?

If you suspect that 1.1V is too low, then try adding more capacitance to the output of the converter, in parallel with the existing MLCC capacitor.

If there is a resistive divider that provides voltage feedback to the motor controller, then measure the voltage at the junction of the divider. If the converter is operating correctly, then this feedback voltage should be equal to the internal reference voltage within the controller.

_________________
A backup a day keeps DR away.

Hi
thanks for your hints.

FIRST OF ALL: I MADE A TERRIBLE MISTAKE!
The drive I'm writing about is a HDT721010 which is a 1TB 3.5" HDD. The HTS also exists and would be a 100MB 2.5"

The MCUs are different, although they seem to use the same pinout. I've checked the center point voltage of the Vcore feedback divider, it's 1.0 volts for both PCBs.
So either one of the resistors has drifted causing the Vcore to drop, or the 1.1 volts are pretty fine.
As I don't have any information on the used motor combo I cannot tell which pin is power good or reset to the MCU.

@pcimage: I'll look up the numbers tomorrow.

At the moment I think I'll get a PCB with the same version code on the MCU on eBay or something and give it a try.

The exact model data:
HDT721010SLA36
P/N 0A38016
Sticker on SATA Connector:
0A29989
BA3129-Mzh916-V4YW