Hitachi h3d10003272s not spinning up

[pcpete]

I have the following drive not spinning up. I do not have any shorts to ground on either the 5v or 12v, so I am assuming the tvs diodes are good. When looking at the board, I am not able to follow how either the 12v or 5v get past the starting point, it seems both rails must continue on the back side. Any suggestions on repairing this board? Is this a board where I can get a donor and just transfer the firmware via the 8 pin chip?

Attachments

[fzabkar]

Measure the voltages at the 100 and 1R1 coils nearest the motor connector.

[pcpete]

Measure the voltages at the 100 and 1R1 coils nearest the motor connector.

2.65 and 1.28

If it matters, that is with the board removed from the drive

[pcpete]

Just because the drive doesn't spin it doesn't mean that the PCB is bad.

Do you have some sort of firmware tool ?

Test the PCB this way :

viewtopic.php?f=1&t=37548

IF PCB does respond by ATA most likely PCB is not the problem.

No firmware tools. I do have a ddi, it just says drive unresponding

[fzabkar]

Those two voltages appear to be in the ballpark.

[pcpete]

Place the PCB only connected to DDI. Does it show DRDY / DSC after a while (it should be BSY first) ?

ata: DRDY DSC (no BSY)

[pcpete]

Those two voltages appear to be in the ballpark.

what do those good voltages mean? Are those the ones spinning up the motor?

[fzabkar]

Vcore = +1.28V
Vio = +2.65V

Those are the supply voltages for the MCU, SDRAM and serial flash memory. The motor and VCM require +12V.

There is a third voltage which is the negative supply for the preamp (-5V ?). It can be measured at the leftmost of the two 100 coils near the TVS diodes.

If this voltage is absent, then measure the resistance between ground and this test point with the PCB unpowered but mounted on the drive. This will be the resistance of the preamp.


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

Attachments

[pcpete]

I do have -5v where you asked. Does that indicate health of the preamp?

[fzabkar]

@pcpete, as Spildit says, the PCB is most probably OK. I'm assuming that your latest measurement was done with the PCB on the drive. If so, then the presence of -5V confirms that the preamp is not shorted.

Are you able to read the LE25FU206 IC in a device programmer?

https://4donline.ihs.com/images/VipMasterIC/IC/ONSM/ONSMS37326/ONSMS37326-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0