Hi m8:s

anyone who can be kind and show me where the fuse/diode on this dead pcb from this WD My Studio 2TB.
I have couple of same PCB but from 1TB Studio i can use spare parts needed for repair.

Pic attached of the board.



Board is totally dead.

Allt the best!

Thx

First question is why do you want to repair the adapter? To access the HDD?

If I were approaching this problem, I would check the onboard power supplies.

AFAICT, capacitor C101 (220uF, 35V) is the main filter capacitor. It should have 12V across it. I'm not sure how diode D1 is connected, but I would measure the voltages between ground and each of its pins.



Next I would check for the presence of +5V at the 150K coil, or across the output capacitors. I have attached a typical application circuit for the NX2838 IC.



Then I would measure the voltages at L4 and L2, and across their associated capacitors. I suspect that these may be the Vcore and Vio supplies for the Oxford Semi bridge IC. The FW843 chip requires an external 3.3V supply which may also be provided by one of these regulators.



I'm not certain about the functions of Q2, Q1, Q4, and D5. We could examine these later if necessary.

References:

NX4110, Microsemi, 1A SYNCHRONOUS BUCK SWITCHER WITH FET, 1MHz, SOT23-5L, 2.8V to 5.5V:
http://www.microsemi.com/document-porta ... 4110ds-pdf
http://datasheet.eeworld.com.cn/pdf/MIC ... 0CZ1TR.pdf

NX2838, Nexsem/Microsemi, 30V Adj HF Single Synchronous. Controller + 3.3V/500mA LDO:
http://www.microsemi.com/document-porta ... 6-nx2838ds

BAT54A, dual Schottky diode, marking L42, 30V, 200mA:
http://www.fairchildsemi.com/ds/BA/BAT54.pdf

AO4840, ALPHA & OMEGA Semiconductor, 40V, 6A, Dual N-Channel MOSFET,
http://aosmd.com/pdfs/datasheet/AO4840.pdf

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

SSC53L, Vishay General Semiconductor, Schottky Rectifier, 30V, 5A:
http://www.vishay.com/docs/88885/ssc53l.pdf

AO4425, ALPHA & OMEGA Semiconductor, 38V, 14A, P-Channel MOSFET:
http://aosmd.com/pdfs/datasheet/AO4425.pdf

FW843, LSI Logic, IEEE 1394b Bilingual Three-Port Cable Transceiver/Arbiter, 3.3V supply, on-chip 1.2V regulator:
http://www.lsi.com/downloads/Public/139 ... _FW843.pdf
http://www.lsi.com/products/networkingc ... FW843.aspx

OXUF943SE-LQAG, Oxford Semiconductor / PLX Technology, FireWire 800 or USB 2.0 to SATA Controller with Encryption:
http://www.plxtech.com/OXUF943SE
http://www.mouser.com/ds/2/327/roduct_B ... -16680.pdf

_________________
A backup a day keeps DR away.

dmarques - "encrypted"

_____________________

fzabkar - Wow, that was an outstanding response to my question. I am very grateful and i owe you one!

Ill get back with results asap.

Thanks again m8!

-eazycut

Couldn't you just transfer the serial EEPROM on the bridge board from patient to donor? Wouldn't that take care of any incompatibility issue?

_________________
A backup a day keeps DR away.

Hi m8.

You mean the 8-leg cips, both of them?

-eazycut

Hi m8.

I have measured above now and here are the results m8.







In the last photo you see that i only get 1,44v on the dead pcb and on the good board i get 3.7v. all other measurements where the same betwwen the boards.

what do you think?

cheers m8.

-eazycut

I can't see the markings on U2, but I suspect that it may be a serial flash memory.

_________________
A backup a day keeps DR away.

yes, it is a serial flash memory – W25X40A: 4M-bit / 512K-byte (524,288)

the marking on U2 is following:
winbond
25X40AVNIG
1017

http://www.datasheetarchive.com/dl/Data ... 254423.pdf

what do you say?

Thx m8.

I don't understand why the "150K" coil is measuring 12V. I must be misinterpreting that section of the circuit. There has to be a large 5V DC-DC converter somewhere.

It appears that the NX4110 / L4 regulator is producing a nominal +3.3V supply. The NX4110 / L2 regulator appears to be producing the same voltage on your good board, so I'm wondering whether one supplies the FW843 chip and the other supplies the OXUF943SE.

Your 1.44V voltage measurement is strange. It appears to be suggesting that there is 3.7V on one side of L2 and 1.44V on the other side. That can't be right.

As for the flash memory, ISTM that this is the only difference between your donor and patient PCBs, so transferring U2 to your donor should get you going. That is, unless each OXUF943SE IC has some unique embedded code.

_________________
A backup a day keeps DR away.

Hi m8.

ill check it up as soon as i have time. this one is not an emergency case, so i have time on this one. Ill come back asap.

many thx!

/eazycut

It is very possible that you could set up an encryption/decryption filter to simulate the USB bridge. I've done it for WD My Book drives using other encryption chips.