HDD Rescue [WD10EADS-11M2B2], before irrecoverable mistake

[yychern92]

Hi helpful people, I have a HDD that wouldn't spin up and it wouldn't be recognized when plugged in to PC. It's a WD Caviar Green packaged as External HDD 1TB.

I've done the following checks:
SATA/USB Converter: tried with other HDD so that's not problem, and used another SATA/USB Converter too same result.
Diodes: D1, D2, D3, D4 all not shorted
Motor: all 4 contacts are shorted to each other (I'm guessing there was no burnt coil then?)
J6: bottom two pins not giving any voltages upon powering up, and top two pins giving constant low voltage, i cross-checked with WD10EZED, and eventually the replacement PCB that I got, that wasn't supposed to be the case, the pins should have fluctuating voltages upon startup.
Hence, I'm guessing that this is a PCB fault.

I've ordered for the PCB number 2060-701640-007 REV A, however there are a few differences which i will type out as below, original first, replacement second:
Serial Number: 2061-701640-707 01PD4 XC A156 01VJL 0004350 0354; 2061-701640-X07 02PD4 XF AN18 7B62 C 0003390 0393
U12: Winbond 25X20ALNIG; can't see but shouldn't be Winbond
U2: EtronTech EM6AA160TSA-5G(O027G11AOA404.117N); hynix007E-A C HY5DU121622DTP-D43
C17: not available; available
U22: not available; available
SK3: not available; available
SK4: not available; available
I've also attached the images of the PCB's

I've done the swaps for ROM/BIOS even before realizing the differences between the PCB's, and upon swapping U12, I've realised that my continuity test on the pins are shorted pin 8 and pin 7 which are inherently shorted on both PCB's, pin 8&7 short-circuited with less than 50 Ohms with pin 6, similarly pin 6 and pin 3 short-circuited for less than 50 ohms. I was worried that powering up the board would damage the ROM/BIOS and completely destroyed the chance of recovering this HDD.

However, I woke up today and test after almost 6 hours later, pin 8&7 no longer short-circuited with pin 6, similarly no continuity observed between pin 6 and pin 3. Instead, pin 8&7 has 9.5MOhm observed with pin 6, and 0.58MOhm observed between pin 6 and pin 3. I'm not sure why but it changed this morning.

My question then:
1) does serial number (sticker on the back of PCB) matter or just the PCB number alone will suffice for matching replacement?
2) difference in components on both PCB boards are fine too?
3) I know that U12 is the ROM/BIOS, but does it tie to the pre-amp/header and thus without U12, platters swap would still be okay for data recovery eventually?

Thanks very much for your help, HDD recovery services are rather limited in my region of residence and hence I'm DIY-ing this.

Attachments

PCB Comparison Front

PCB Comparison Rear

[fzabkar]

I can't say whether the replacement board will work. FWIW, here are my observations:

1/ The PCB on the right has a "blister" on the SMOOTH chip. Is that the faulty PCB? Did you try to spin up the drive with the replacement PCB, without transferring the ROM? I notice that the same PCB is used by Caviar Blacks and Greens, which spin at 7200 and 5400 RPM, respectively. I don't know what would happen if you spun up a Black with a Green PCB. Would the Black's heads fly much lower at 5400 RPM, and would this be dangerous?

2/ EM6AA160TSA-5G is a 2.5V, 16M x 16 bit DDR SDRAM whereas HY5DU121622DTP-D43 is a 2.5V, 32M x 16 bit DDR SDRAM. I don't know if this difference in RAM capacity will affect compatibility.

3/ The PCB on the right has a 3.3V pass transistor at Q1 whereas the board on the left does not. Therefore I suspect that the ROM chip on the right PCB runs off a 3.3V supply whereas the ROM on the left PCB is powered from 2.5V. This may affect compatibility. You would need to refer to the datasheets to be sure.

4/ SK3, SK4 are shock sensors for rotational vibration sensing. U22 is an op amp which amplifies the vibration signals.

Here is my collection of datasheets:
http://www.users.on.net/~fzabkar/Datasheets/DATAURLS.HTM

[yychern92]

I can't say whether the replacement board will work. FWIW, here are my observations:

1/ The PCB on the right has a "blister" on the SMOOTH chip. Is that the faulty PCB? Did you try to spin up the drive with the replacement PCB, without transferring the ROM? I notice that the same PCB is used by Caviar Blacks and Greens, which spin at 7200 and 5400 RPM, respectively. I don't know what would happen if you spun up a Black with a Green PCB. Would the Black's heads fly much lower at 5400 RPM, and would this be dangerous?

2/ EM6AA160TSA-5G is a 2.5V, 16M x 16 bit DDR SDRAM whereas HY5DU121622DTP-D43 is a 2.5V, 32M x 16 bit DDR SDRAM. I don't know if this difference in RAM capacity will affect compatibility.

3/ The PCB on the right has a 3.3V pass transistor at Q1 whereas the board on the left does not. Therefore I suspect that the ROM chip on the right PCB runs off a 3.3V supply whereas the ROM on the left PCB is powered from 2.5V. This may affect compatibility. You would need to refer to the datasheets to be sure.

4/ SK3, SK4 are shock sensors for rotational vibration sensing. U22 is an op amp which amplifies the vibration signals.

Here is my collection of datasheets:
http://www.users.on.net/~fzabkar/Datasheets/DATAURLS.HTM

Thanks so much for your reply @fzabkar!

1) The one on the right is the replacement, the one on the left is the original, i think it's a stain than a blister? I didn't try to power up the HDD with the replacement PCB before swapping the ROM's, I'm worried that would make me lose data, would it?

2) noted, i'm even less sure of it

3) Ah, so that's what the additional voltage regulator is about, for additional 3.3V. I can't get the model number for the replacement PCB's ROM, but I've checked my original ROM, it's 2.5V nominal voltage, although can handle up to 3.6V, I wouldn't want to risk it though. losing ROM can be lethal I suppose? As in that's it for me, no more chance of recovering data after that.

4) should I attempt to remove them?

I've contacted the seller, he seems to suggest that PCB number is the only thing that matters, as long as it matches, anything else doesn't matter. Maybe I should attempt to buy another replacement PCB then? that has the exact same components? but how can I ensure my next purchase wouldn't end up being slightly different like what I currently have now?

[yychern92]

I've managed to retrieve the code written on the replacement PCB's ROM:
Pm25w0202-AE1010-M203300
those highlighted in red could be G/8/C respectively, tough to see

[fzabkar]

I would give it a go. However, it might be worth taking some voltage measurements on your original PCB at L1, L2 and D2 near the SMOOTH IC. You should see +1.2V and +2.5V.

[yychern92]

I would give it a go. However, it might be worth taking some voltage measurements on your original PCB at L1, L2 and D2 near the SMOOTH IC. You should see +1.2V and +2.5V.

I've powered it up, nothing smoked, which was rather a good sign. However, upon connecting the replacement PCB with original ROM to the HDD, it's still doing the same as before, the HDD is not spinning up at all. I've measured the pins at J6, at least there are some fluctuating voltages now


to measure voltages at L1, L2 and D2 on the original PCB may be impossible now, as I stupidly dropped some solder onto the main IC legs, i didn't want to power up and cause even more damages on the original PCB's.

[pepe]

It won't do any harm to the drive, but the question is wether preamp is ok or it is busted too. If it is, well, then it can ruin the data on the disks beyond recovery.
pepe

[fzabkar]

If you place a business card between the PCB and HDA connector, does the drive spin up?

Are you sure you can't hear any faint stiction-like noises?

[yychern92]

It won't do any harm to the drive, but the question is wether preamp is ok or it is busted too. If it is, well, then it can ruin the data on the disks beyond recovery.
pepe

how do you know if the pre-amp is okay?

[yychern92]

If you place a business card between the PCB and HDA connector, does the drive spin up?

Are you sure you can't hear any faint stiction-like noises?

which of the HDA connectors should I cover? the header or the spindle motor? at the moment I hear nothing after swapping the ROM to the replacement PCB to use

[BGman]

2061-701640-707 is not compatable with 2061-701640-X07 .Different ROM size and maybe something more...
It's Dragon Fly 2 isn't it. At the time I've had a lot of troubles with them . Try to find exact match...
I've seen 96k, 128k and 256k ROMs of these drives...

[yychern92]

2061-701640-707 is not compatable with 2061-701640-X07 .Different ROM size and maybe something more...
It's Dragon Fly 2 isn't it. At the time I've had a lot of troubles with them . Try to find exact match...
I've seen 96k, 128k and 256k ROMs of these drives...

It's been tough trying to find details regarding the ROM for X07's, but that's the sticker number not the PCB number. The PCB numbers are exact match tho

[BGman]

They used several variants of 701640 PCB in your case Rev 07. Difference might be ROM size, DRAM size, motor controller or something else....

[yychern92]

They used several variants of 701640 PCB in your case Rev 07. Difference might be ROM size, DRAM size, motor controller or something else....

you're right, but both the PCB numbers are exactly identical, down to the Rev A.
What's different then, is the Serial Number/Sticker that's on the PCB, as shown on the images.

[pepe]

it might work if the correct rom is used, but since yours is dead, it is not really easy to make a compatible pcb. So if your data is important i recommend contacting someone who's able to deal with it, ie a dr company.
I am not sure who on this forum is nearest to you.

pepe

[fzabkar]

If you place a business card between the PCB and HDA connector, does the drive spin up?

Are you sure you can't hear any faint stiction-like noises?

which of the HDA connectors should I cover? the header or the spindle motor? at the moment I hear nothing after swapping the ROM to the replacement PCB to use

Cover the 20-pin J1 connector. That disconnects the preamp and voice coil from the PCB.