Author Topic: toshiba harddisk pcb repair  (Read 573 times)

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Offline BucketBoss

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toshiba harddisk pcb repair
« on: March 03, 2019, 11:40:03 pm »
Hi there, recently one of my harddisks stopped working. it spins up but wont appear in bios, desktop and so forth. i have a replacement pcb from an identical hdd but when i swapped the pcbs the old disk with new board didnt work nor did the new disk with the old board. i set the voltmeter to continuity and tested some of the smts, which i think were diodes, on both boards and found one (highlighted) on the old non functioning board that reads 0.345 and the corresponding smt on the new board reads 1.121. To me it seems like this is the faulty component and replacing it should fix the harddisk but my electrical knowledge only goes as far as knowing which way batteries go in a torch. As long as this is the only problem does it sound like this will work? any advice is greatly appreciated.
 

Offline fzabkar

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« Last Edit: March 04, 2019, 03:35:14 pm by fzabkar »
 

Offline BucketBoss

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Re: toshiba harddisk pcb repair
« Reply #2 on: March 04, 2019, 09:34:01 am »
picture didnt upload. here it is
 

Offline BucketBoss

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Re: toshiba harddisk pcb repair
« Reply #3 on: March 04, 2019, 09:34:51 am »
oh
 

Offline Gyro

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Re: toshiba harddisk pcb repair
« Reply #4 on: March 04, 2019, 10:13:19 am »
That looks like one of the supply rail TVS protection diodes, possibly damaged by a surge. A simple continuity test doesn't really give meaningful results - it needs to be tested as a zener diode, or at least using the diode test function to see if it is shorted. Your continuity test does seem to indicate some sort of difference though.

Simply replacing it might solve the problem, but as explained in fzabkar's link, it might be too late for that now if the 'parameters' / fw area of the HDD has been corrupted.

It might still be worth a try though, you've nothing to loose at this point.
Chris

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Offline testpoint1

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Re: toshiba harddisk pcb repair
« Reply #5 on: March 04, 2019, 11:50:52 am »
if no motor running, as usual, it is power supply problem, just check it.
 

Offline Gyro

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Re: toshiba harddisk pcb repair
« Reply #6 on: March 04, 2019, 12:59:18 pm »
Good point. It would also be useful to know whether the spindle motor spun up with the other PCB (don't try it again!). If the disk didn't spin then it wouldn't be possible to corrupt anything. It would also make the reason more puzzling though.
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline magic

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Re: toshiba harddisk pcb repair
« Reply #7 on: March 04, 2019, 01:17:52 pm »
FYI,
it spins up

I wouldn't worry much about data corruption if the problem is clearly electric in nature, i.e. short from 5V to ground.

OP, check with a continuity tester if the "north" end of that diode is connected to ground ("south" is clearly at 5V). So far everybody's guess is that it's a TVS and therefore the other end should go to ground.
If so, remove it, switch DMM to diode mode and take a measurement with red probe on the 5V end of the TVS and black on ground. It should come the same as on the other disk with good TVS.
Also, check resistance of this blue thing which connects the TVS to 5V, it probably is some kind of resettable fuse.
 

Offline orbanp

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Re: toshiba harddisk pcb repair
« Reply #8 on: March 04, 2019, 01:31:04 pm »
Here is my experience with hard disk repair:
https://www.eevblog.com/forum/repair/hard-disk-recovery/msg1310786/#msg1310786

I guess I was lucky.

Regards, Peter
 

Offline fzabkar

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Re: toshiba harddisk pcb repair
« Reply #9 on: March 04, 2019, 09:16:28 pm »
The OP's drive spins up -- it just doesn't identify itself. This means that the PCB is most probably OK. The problem is most likely an internal one, possibly a corrupted or unreadable grown defect list or SMART module.
 

Offline FrozenHaxor

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Re: toshiba harddisk pcb repair
« Reply #10 on: March 05, 2019, 10:33:11 pm »
From experience when those diodes fail, it shorts out the entire 12V line, most likely incompatible firmware between boards. You can try swapping the EEPROM chips from old board to the new and trying it that way, would help if the controller is dead, but unfortunately its most often that the EEPROM itself actually goes bad. Chances are nix.
 

Offline fzabkar

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Re: toshiba harddisk pcb repair
« Reply #11 on: March 05, 2019, 11:59:46 pm »
The part number on the PCB (OA90380) indicates that the drive is a rebadged Hitachi. The problem is still most probably an internal one.

https://sep.yimg.com/ay/yhst-14437584971410/91711045-6.gif
https://www.hdd-parts.com/17110832.html
 


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