Western Digital WD400EB 12V power supply line bad - schemati

[mediaman]

Hello, I have the above and the 12V power supply reads semi-short, compared to another good disk of same series. I have checked the obvious diodes, caps etc in the 12v line area and all seem good. Any help on where to find the schematics? I know the disk died in a PC with a blown PSU so am sure the search area is correct, I just can't locate the damaged PCB area. THANKS!

[rchadwick]

Well, the sure-FIRE method is to simply put the shorted line (+5 or +12) on a bench supply, and crank up the current until you see something smoke. You could also just feel for a warm component at a lower current, but it just isn't as much fun

BTW, Are you sure it's not a diode across the input?

[mediaman]

Hello Chadwick, thanks for the kind reply. unfortunately, as with most things in life its not so clear, its not a full blown short, just a very much lower R than the similar pins on the good board. there are only 3 diodes on the boards and all seem fine. The problem, looking futher, seems to be in the upper left hand (board mounted face down to disk, pins towards ones chest) where the four pin connector enters the drives motor. The central two pins (on the PCB) also appear shorted. Any ideas on the circuit diagrams? I'm sure the WD series are very very common, and over voltage failures on these also.... back to google..

cheers

[harddrivespecialist]

I believe it would be easier to get a new board.

[mediaman]

can you recommend a reliable source?

[rameez]

Give the full model of the hdd like Wd400bb-00cpf0 i will check in my stock for pcb .