Good morning,

I've this WD 3.5' portable hard drive from our client, the drive is in working condition but it simply doesn't spin up. We had identified the problem which is the USB controller board (faulty.jpg).

The working unit (working.jpg) spins up the drive but obviously it doesn't show the data on the screen.

Now we are just wondering whether it works if we swap U2 chip to the donor board (working.jpg)? Or there's something else we should pay attention to?

You help/ advise will be very much appreciated

Thanksss.

The two boards have different bridge ICs (Asmedia vs JMicron). The easiest solution may be to repair the faulty PCB.

Does the faulty PCB show up in Windows Device Manager? If so, then this would confirm that the bridge IC and its power supplies are OK. You could use UVCView or USBDeview to confirm this.

http://www.nirsoft.net/utils/usb_devices_view.html
http://download.microsoft.com/download/ ... ew.x64.exe
http://www.users.on.net/~fzabkar/USB_ID ... ew.x86.exe

I notice that U4 (APM4532 dual MOSFET) has a black spot on it. If this IC is faulty, then all you would need to repair the board would be two wire jumpers. Let me know what you find with UVCView.

Also measure the voltages on each pin of U4.

_________________
A backup a day keeps DR away.

HI fzabkar,

The faulty PCB doesn't power up the HDD at all, we tried it on another HDD and it gave the same result. We used the same power supply on the working PCB, it powered up the HDD.

So

1. Power supply is OK
2. HDD is OK
3. Faulty PCB is NOT OK

About the U4, it isn't really a burnt mark. You may see the attached snapshot that I told under the microscope.

Thanks

I know this sounds silly but, can it be the power supply port on the PCB?

Here are my guesses for the voltage test points:

_________________
A backup a day keeps DR away.

I just checked my notes. ISTR two similar PCBs, one with the Asmedia bridge and the other with a JMicron bridge. Perhaps they are pinout and code compatible, in which case swapping U2 may work???



For reference, here are the datasheets for the other chips:

NX7101IDM, Microsemi, 2A High Voltage Synchronous Buck Converter, 4.75V- 18V, 340kHz:
http://www.microsemi.com/document-porta ... -datasheet

APM4532, Anpec, Dual Enhancement Mode MOSFET (N-and P-Channel), 30V/5A, -30V/-3.5A:
http://www.anpec.com.tw/ashx_prod_file. ... M4532K.pdf
http://www.audiolabga.com/pdf/APM4532K.pdf

Pm25LD020, Programmable Microelectronics Corp, SPI (dual output), 2.3V - 3.6V, 2Mbit, Serial Flash Memory:
http://www.chingistek.com/img/Product_F ... %20v04.pdf

_________________
A backup a day keeps DR away.

You might like to try a USB 2.0 cable to eliminate any USB 3.0 connection problem.

_________________
A backup a day keeps DR away.

Good morning fzabkar,

Thank you so much for all the advise and very useful links/ info.

I've transferred the U2 over to the donor PCB, it detected in the computer system but the partition tables don't show up.

I had tried to scan the drive for a quick 5min and it does show the entire partition tables with a list of folders & files in there. Opened a few random files and obviously a few OK & the rest are NOT. So I'm scanning the entire drive now.

By the way, this is a 4TB HDD and when I scanned it in R-Studio it shows one HFS (450GB) and another one 'Empty space18'. Am I OK to assume the second partition is totally empty? I checked the drive in hex editor and the hex value of the drive looks identical after certain sectors. It looks to me that those spaces are not filled. Correct me if I'm wrong.

The reason I asked this is because scanning a 4TB drive via USB2.0 is a real pain and customer kinda need it quite urgently.

Thanks again

The drive is encrypted by the bridge board. You need to acess the data via USB, preferably USB 3.0.

I would prefer to fix the original board.

Alternatively, try this freeware:
http://www.hddoracle.com/viewtopic.php? ... 7870#p7870

BTW, some WD USB enclosures are configured with 4KB sector sizes. When you remove a drive from such an enclosure, and if the enclosure is the non-encrypting type, the partitions will appear to be smaller by a factor of 8. Therefore a 4TB partition will be detected as a 500GB (= 465GiB) partition.

_________________
A backup a day keeps DR away.