ST31000340AS Board Issues - Suggestions?

[Dizidago357]

Hi,

We have a Seagate model ST31000340AS, with firmware of SD81, site of WUXISG, and a serial beginning with 5QJ. The drive was not spinning, so we thought TVS issues. Connected a donor board and the drive spun up. Removed the TVS's on the patient under the assumption that those were bad, but the drive still didn't spin. So performed a ROM swap between that board and the donor. Now the patient with donor board and patient ROM doesn't spin, and the donor with patient board and donor ROM doesn't spin. Swapped the ROMs back and now the full donor has the same results as the full patient (not spinning at all). Pulled a board from our inventory and attached that to the patient drive. The patient spun up. But after a ROM swap, the drive no longer spins up. In Seagate Doctor after the swaps the boards no longer go ready or ID, something that usually happens with just the boards on these drives.

I thought maybe something on the patient is killing the boards, but if that is the case then you would think the boards would die after the first time connected, not just after ROM swaps.

Does anyone have any ideas or has anyone seen anything like this in the past?

Thanks,

Dizi

[harddrivespecialist]

ROM might be corrupted and corrupted your donor PCB.

[drc]

Did you verify the EEPROM is making a good connection? Anything in the terminal?

[fzabkar]

The drive was not spinning, so we thought TVS issues. Connected a donor board and the drive spun up. Removed the TVS's on the patient under the assumption that those were bad ...

Why? A resistance test with a DMM would have told you whether they were OK. Moreover, if either TVS diode were shorted, then it would have shut down your power supply.

ISTM that there is something wrong with the Vio supply on the patient PCB. It probably killed the "ROM". You then transferred the bad ROM to your donor PCB, with the expected result. That is, your good donor PCB with your bad patient ROM failed to spin up either drive. In addition, your patient PCB, with its Vio fault, also killed your donor ROM. Now both ROMs are bad, in which case restoring each ROM to its original board once again results in no-spin for both drives.

IMO, the next logical step would to measure the ROM's supply pin (#8). I suspect that it may be sitting at +5V instead of +3.3V.

[Dizidago357]

Hi,

The ROM is making a good connection on both, even removed and reconnected both ROMs (on the first donor swap) just to be sure.

@Fzabkar,

When I measure, I assume I use 20VDC? Or should I use 2VDC?

Thanks,

Dizi

[fzabkar]

20VDC

You won't do any damage to either your meter or your job by selecting an inappropriate voltage scale.

The Vio voltage would be +3.3V or +2.5V, depending on the design.

So ...

2V < 2.5V / 3.3V / 5V / 12V < 20V

[BlackST]

Why concentrate on PCB ? (In other words : if ROM is lost / broken or PCB is completely toasted / unavailable is it declared UNRECOVERABLE ?)

[fzabkar]

A post mortem is always useful, IMO, especially for someone who appears to be at the start of a steep learning curve. At the very least the OP needs to know if the fault was there beforehand, or whether it was the result of improper soldering technique.

[BlackST]

Don't think so, especially if they get paid only if they recover data.
Anyway, after killing 2nd pcb, *maybe* re-diagnose is necessary.