Author Topic: Seagate barracuda hard drive  (Read 4912 times)

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Offline G7PSK

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Seagate barracuda hard drive
« on: August 23, 2014, 04:45:21 pm »
I have a seagate barracuda 7200 hard drive that I have removed from my mother in laws computer to replace with a larger unit.
Although it works there is what appears to be a blown diode on the board just above the sata power connection and next to an inductor. The one adjacent to it is labeled 54 40 google shows this a schottky diode, is this correct as the ones shown are all axial leads and I cannot find them as smd's.
Sorry about the photo quality I used my phone
 

Offline leppie

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Re: Seagate barracuda hard drive
« Reply #1 on: August 23, 2014, 04:55:21 pm »
BAT54 maybe?

If you have a STM32 F4 discovery, you can source one from the SWD output (if you dont use it)
 

Online wraper

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Re: Seagate barracuda hard drive
« Reply #2 on: August 23, 2014, 05:53:03 pm »
No way it is BAT54. This is for power input protection from reverse polarity and maybe overvoltage. So it is either schottky or TVS diode.
 

Offline DmitryL

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Re: Seagate barracuda hard drive
« Reply #3 on: August 23, 2014, 09:24:00 pm »
I have a seagate barracuda 7200 hard drive that I have removed from my mother in laws computer to replace with a larger unit.
Although it works there is what appears to be a blown diode on the board just above the sata power connection and next to an inductor. The one adjacent to it is labeled 54 40 google shows this a schottky diode, is this correct as the ones shown are all axial leads and I cannot find them as smd's.
Sorry about the photo quality I used my phone

You might have taken a sharper picture... I've seen case like this. It was a blown TVS across HDD power connector.
I presumed that the cheap low-quality computer PSU started to generate high ripple voltage because of the capacitors degradation, TVS tries to cope with that and died :) Surprisingly, HDD worked well after I desoldered blown TVS.
Check the computer PSU, next time it may blow something else
 

Offline leppie

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Re: Seagate barracuda hard drive
« Reply #4 on: August 23, 2014, 09:37:09 pm »
No way it is BAT54. This is for power input protection from reverse polarity and maybe overvoltage. So it is either schottky or TVS diode.

BAT54 is a schottky diode...  :palm:
 

Online wraper

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Re: Seagate barracuda hard drive
« Reply #5 on: August 23, 2014, 09:57:49 pm »
No way it is BAT54. This is for power input protection from reverse polarity and maybe overvoltage. So it is either schottky or TVS diode.

BAT54 is a schottky diode...  :palm:
Yes, but it is in completely different case and low current :palm:. And you need to be crazy to assume that someone have a spare  STM32 F4 to get a diode from it. Moreover there are 4 variants of BAT54 with different diode connections to pins.
 

Online wraper

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Re: Seagate barracuda hard drive
« Reply #6 on: August 23, 2014, 10:09:38 pm »
here is a picture from the same PCB (also crappy)
 

Offline G7PSK

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Re: Seagate barracuda hard drive
« Reply #7 on: August 24, 2014, 08:33:06 am »
The crazy thing is the hard drive still works despite the top having been blown right off the diode. I am uploading a better picture today.
 

Online wraper

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Re: Seagate barracuda hard drive
« Reply #8 on: August 24, 2014, 08:47:46 am »
There is nothing crazy. Pretty sure it is connected between power rail and GND. Therefore when it became open that did not affect working. You can just replace it with TVS diode with appropriate rating for the power rail where it is connected. +1 about that you need to check PSU.
 

Offline free_electron

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Re: Seagate barracuda hard drive
« Reply #9 on: August 24, 2014, 10:18:21 am »
Thats the 5 volt rail TVS diode.
Professional Electron Wrangler.
Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline G7PSK

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Re: Seagate barracuda hard drive
« Reply #10 on: August 24, 2014, 11:05:35 am »
Thanks for all the reply's and advice. I checked the voltage on a known good power supply and found 5.18 volts across it when checked on the computers power supply it was 5.12 volts. I have ordered some 6 volt smd tvs diodes will that do.
 

Online wraper

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Re: Seagate barracuda hard drive
« Reply #11 on: August 24, 2014, 11:10:53 am »
Multimeter won't show the crap happening on the rail. You need either to use oscilloscope and measure under load or unscrew the PSU and check if there are not any bulging capacitors.
 

Offline G7PSK

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Re: Seagate barracuda hard drive
« Reply #12 on: August 24, 2014, 03:32:20 pm »
The scope shows just under 200mV peak to peak ripple. Took the power supply apart and could not see any bulging or leaking capacitors. Could be that it was a weak diode or there was some form of transient on the power input, I will try replacing the diode and see what happens the drive is expendable as its only a 40GB one I have flash sticks bigger than that.
 

Offline leppie

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Re: Seagate barracuda hard drive
« Reply #13 on: August 24, 2014, 07:21:26 pm »
No way it is BAT54.

Arghhh! I never did read "adjacent" in the OP  :palm: Sorry dude  :-[
 

Online SeanB

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Re: Seagate barracuda hard drive
« Reply #14 on: August 24, 2014, 07:24:32 pm »
I have a number of those drives, removed from old computers. They are good for replacing old IDE drives in dead obsolete computers.
 


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