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Do you know what this is???

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trebor3683

New Member
I have a Samsung 500GB hard drive that stopped working unexpectedly. I noticed a small puff of smoke. Took it out and when I looked at the back of the drive I found a burnt component (which I am trying to identify) on the PCB. Some of my research has suggested it may be a TVS Diode. If it is, what info do I need for a replacement? Will any diode work? I have tried searching for the numbers and letters together and separate with no luck. Requests sent to Samsung for a new PCB have not been answered. Does anybody have a number or web address that they answer?

Illustrated in the picture below (click to enlarge) are arrows pointing to the bad part #1 and arrows pointing to #2 a similar component that appears to be alright. Thank you!

#1 is pointing to the burnt out part with the following info on it (as best as I can make it out)
Top line: [Co. Logo] 814
Bottom: H E

#2 is pointing to a similar component with the following info on it.
Top line: [Co. Logo] 810
Bottom: L E
:confused:

Samsung HDD Back wLabel.jpg
 

blueroomelectronics

Well-Known Member
Please don't triple post.

It's probably going to be cheaper to purchase an identical drive and swap the PCBs then it would be to order a replacement PCB from Samsung.
 

Pommie

Well-Known Member
Most Helpful Member
The item in the top left also appears to have released the magic smoke. As already mentioned it will probably be cheaper to get a new drive.

Mike.
 

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trebor3683

New Member
I have the new drive ready and waiting but I need to get the information from the old drive by repairing the PCB. I have been looking for a donor board but the firmware and part numbers do not match. Even date codes found are too far off. The sick part is that the drive is less than a year old and it was the backup drive. Main drive corrupt after defrag. Yes, it's under warranty but the data is what I need. Thanks!
 

trebor3683

New Member
Hi again,

It's definitely the #1 as marked in the first picture. I am including closeup pictures of both areas, so Pommie if you have any further assistance I would appreciate it. Thanks again!


This one is labeled #1 on the first picture.
TVS Diode Close-upLg3.jpg


This is the other one below with the B2 Y815 on it. That chip has a manufacturing dimple in the middle.
Close-up Chip.jpg
 

Hero999

Banned
Replacing the PCB is probably not economical but I understand that the data on the drive is probably worth to you more than the drive itself.

There are probably other damaged components so replacing the diode probably won't help. Try any Schottky diode with a current rating > than the current rating on the nameplate of the hard drive if you like but don't expect any success.

Your best bet is to have a look on ebay for exactly the same hard drive and cannibalise it. You can probably pick one up cheap if it's got bad sectors the PCB will still be fine.
 
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HiTech

Well-Known Member
Replacing that SMT capacitor is a real gamble. Most of those components are there as support devices to the nearby IC chips. There's a good chance a chip could have problems when one of it's associated components has smoked as bad as that one did. Drives are cheap these days-- just buy a new one from Tiger Direct or New Egg.com.

Whoops! My bad-- I meant diode not cap.
 
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trebor3683

New Member
Hi everyone,

I found out the diode was a 5v TVS diode 600w so I ordered a couple from Digi-Key (53 cents each). Should be here today so I'll give it a try over the weekend and let you all know what happens. It's worth a buck to give it a try. Thanks for all your help.

A Happy, Healthy & SAFE Fourth of July to everyone.

Bob...
 

trebor3683

New Member
:) :) Success :) :)

Hi everyone,

The new TVS diode worked perfectly. The drive spun up normally and read everything. I had plenty of time to make two data back-ups, two disc images and it's still going strong. Now it's time to send it back to Samsung under warranty. I'll be posting a photo of the PCB with the replacement diode installed and the specs. The TVS diode is a special type of diode who's purpose is to protect and save the circuit from damage, which it did, but it is not supposed to fail in it's entirety making the device useless. I bought extra diodes just in case - 5v and 12v. If anybody would like to have them for the cost - plus postage (through PayPal) let me know and I'll ship them to you - only within the USA or the UK. Thanks again for your concern.

Bob...
 

Hero999

Banned
Good, I'm glad you got it working.

By repairing it you've probably voided the warranty so Samsung might not take it back.

There's now probably nothing wrong with the drive but I can understand you not wanting to use it.
 

unclejed613

Well-Known Member
Most Helpful Member
the caps were probably tantalums, they have a nasty habit of smoking for no reason. when i see them in audio gear, it's an automatic replacement.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
the caps were probably tantalums, they have a nasty habit of smoking for no reason. when i see them in audio gear, it's an automatic replacement.
Yes, they appeared briefly in domestic electronics, but were soon dropped due to their extremely high failure rate - they commonly (and frequently) go short circuit, or very leaky.
 

Hero999

Banned
I've never had a problem with tantalums and find them more reliable than aluminium electrolytic which tend to dry up. Having said this I know that tantalums are less tolerant of voltage spikes so may be poor design would explain the spontaneous smoking.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I've never had a problem with tantalums and find them more reliable than aluminium electrolytic which tend to dry up. Having said this I know that tantalums are less tolerant of voltage spikes so may be poor design would explain the spontaneous smoking.
I've been servicing TV's etc for 38 years, and Tantalums have been a total disaster - most were used on regulated rails, so spikes were never a concern.

They were just totally useless, continually failing for no reason - which is why all TV manufacturers dropped them.
 

unclejed613

Well-Known Member
Most Helpful Member
apparently i didn't read the post were they turned out to be TVS diodes........

they don't usually go out unless they get spiked somehow...... i would replace your power supply........

and yes, repairing the drive voided the warranty. i would find a non-critical use for the drive.
 

trebor3683

New Member
:D
Hi all,

As far as the TVS diodes go, it appears that they are still around. The hard drive was less than a year old. Be prepared to see them around or should I say look for them. They may be your problem. Given their reputation and reliability you will be sure to come across one soon. Listed below is a brief description from Semtech for informational and non-commercial personal use "What are TVS diodes?" For the full description with simple diagrams click on the link to view in PDF format.



What are TVS Diodes?

Transient Voltage Suppression (TVS) diodes are solid state pn junction devices specifically designed to protect semiconductors from the damaging effects of transient voltages. The electrical characteristics of the transient protection circuit are determined by factors such as junction area, doping concentration, and substrate resistivity. The surge power and surge current capability of the TVS diode are proportional to the junction area. TVS diodes are constructed with large cross sectional area junctions for absorbing high transient current. While the VI characteristic curve of the TVS diode is similar to that of a zener diode, TVS diodes are specifically designed, characterized, and tested for transient voltage suppression. By contrast, zener diodes are designed and specified for voltage regulation.

> Download our "What are TVS Diodes?" application note

http://www.semtech.com/pc/downloadDocument.do?id=509
 

unclejed613

Well-Known Member
Most Helpful Member
i've seen them and i've seen them fail. part of the problem with them failing is that they are spec'ed with a clamp voltage too close to the power supply voltage they are being used with. the same problem exists with cheap AC surge strips using cheap MOV's rated only 5 to 10% higher than the AC line voltage. this operates both TVS diodes and MOVs with a significant amount of leakage current, because they are operating at the edge of their conduction curve. long term heating causes them to fail, as does a small spike on the rail after they are already heated. with TVS diodes, the damage is usually limited to the diode itself, but with MOVs operated in this condition, they are a fire hazard, especially in a plastic outlet strip. TVS diodes and MOVs, if operated as intended, can clamp huge amounts of energy, but if they are pre-heated due to being run "close to the edge", the additional energy they can dissipate is much smaller.
 

unclejed613

Well-Known Member
Most Helpful Member
shown below is the temperature derating curve for a 1.5kw peak TVS diode (the ones in that hard drive are probably a lot smaller rating, but this is an example of how temperature affects the protection abilities of a TVS diode)
 

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trebor3683

New Member
Yes unclejed613 the original TVS diode was much smaller. I was able to replace it with a heftier one - link below is the datasheet for the replacement I used. It is interesting to see how rapidly they drop off with a rise in temperature. Thanks for the info.



http://www.vishay.com/doc?88394
 

unclejed613

Well-Known Member
Most Helpful Member
all all semiconductors have similar derating curves. another habit zeners and TVS diodes have in common is a change in conduction voltage with temperature. generally the rule is related to the breakdown voltage. if it's below 6V the temperature coefficient is negative, if it's above 6V the tempco is positive. 6V zeners and TVS diodes are temperature stable. this is due to a subtle change in the way zeners operate below 6 volts and above 6 volts. below 6V, zeners operate in what is truly the "zener breakdown" region (which is similar to a negative resistance effect), and because of some quirk of semiconductor physics, 6V is the maximum voltage a zener can be made for. above 6V, "zener" diodes operate in a mode called avalanche breakdown, which is more similar to a diode with a very low reverse voltage rating. both effects have opposite temperature coefficients, and at 6V the mix of dopants in the silicon that control these effects is about equal, so a 6V zener is operating in both modes, and the tempco's cancel. this is why you will often see that if a zener voltage above 6V (such as 12 or 18 or 24) must remain temperature stable, strings of 6V diodes are often used.
 
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