Might someone help me identify this?

[InductorNoob]

Hello, this is my first post. Believe me, I hate to be the guy who signs up to a discussion group only to ask a question - and when I find myself in such a position, I'm inclined to also "give something back" to the community who put forth the effort to help and waste their valuable time on me.

I hope I can contribute something to this forum but the intricate world of electronics isn't exactly my forte. I sure as heck will try, though!

So here's my dilemma: I have a 3.5" Seagate Barracuda 7200.10 320GB hard-drive that I accidentally attached to the wrong power supply when it was in an external enclosure. Much to my horror, upon removing it from its casing, I discovered that I was missing one of the shielded power inductors from the PCB. I've examined the remainder of the circuitry with a loupe and haven't found any other visible damage so I'm hoping that by soldering on a new inductor (for about a dollar), I can avoid having to buy a replacement board ($60). And even if I do replace the entire board, I've been told that there's about a 10% chance that I "fried the data, too" so the whole thing is a crap-shoot.

I am hoping that someone, somewhere, can help me to identify exactly what brand, model, and voltage of replacement inductor I need to purchase so that I might be able to get my data back. I contacted Seagate tech-support but was told simply "that data isn't available in our system" and was hung-up on.

Perhaps the following pictures of the board and inductor could help to identify the part I need?

This is the entire PCB:
**broken link removed**

This is a close-up of the area which contains the (now missing) inductor:
**broken link removed**

From what research I've done, it is a shielded power inductor, and the marking "3R3" designates it as 3.3uh. The only problem is (for me) that none of this means much to me as I'm wholly deficient in knowledge on the subject. I've also discovered that there are many different kinds of 3.3uh inductors and I don't know which one I need.

I'm hoping that someone can perhaps identify the maker of the inductor or possibly know a better direction in which I might investigate, since tech-support was of no help.

Thanks for anything you guys can provide to me.

- Josh Brown

 

[Mikebits]

Looks like a ferrite core inductor. Digikey has these, but you need to know the current rating. What is the part number of the little IC near the inductor?

 

[Willbe]

a new inductor (for about a dollar), I can avoid having to buy a replacement board ($60).
And even if I do replace the entire board, I've been told that there's about a 10% chance that I "fried the data, too" so the whole thing is a crap-shoot.

as 3.3uh.

How much current does the inductor need to carry?

So if a new inductor costs $1 and the chance is X that this will fix it you should only spend this dollar if X is more than 1/60, assuming $zero for labor and no chance that you can further damage the unit by doing the replacement.

If your data is worth at least $60/0.9 = $70 you should do the $60 board gamble, assuming $zero for labor and no chance that you can further damage the unit by doing the replacement.

This decision tree has more branches; what is the cost of a clean-slate replacement unit?

 

[rezer]

Looks like a ferrite core inductor. Digikey has these, but you need to know the current rating. What is the part number of the little IC near the inductor?

Good idea Mike. Give us the part number off of the chip, and maybe we can find an app for it in the data sheet.

 

[kchriste]

The inductor appears to be part of a switching regulator circuit.
In the upper left hand corner of the entire PCB, there appears to be a burn mark near the screw. Have you lifted the board off and checked for burnt traces, etc on the flip side? I suspect you have more problems than just a burnt inductor.

 

[rezer]

In the upper left hand corner of the entire PCB, there appears to be a burn mark near the screw. Have you lifted the board off and checked for burnt traces, etc on the flip side? I suspect you have more problems than just a burnt inductor.

That is a fiducial I believe.

 

[RadioRon]

Another option is to get your hands on another scrap hard drive with the identical model number and swap the inductor over from that one. Some people have access to scrap drives through a company IT department or through a friendly local computer store.


Based on appearance, the part might be:
Sumida CDRH4D28C rated at 1.57 Amps.

To confirm, it would be useful to know what the exact dimensions of the inductor are (measured with metric calipers).

I've seen that circle logo on Taiyo Yuden power inductors, but can't find this shape of package in their catalog. Not sure what markings Sumida puts on their parts.

If in doubt, it is relatively safe to get a larger current rating than is necessary.

 

[Torben]

Another option is to get your hands on another scrap hard drive with the identical model number and swap the inductor over from that one. Some people have access to scrap drives through a company IT department or through a friendly local computer store.

I had exactly the same thought. In Vancouver there was (maybe still is) a store called "Cal's Computer Warehouse" where they had bins and bins of old computer hardware. There may be something similar where-ever InductorNoob is.


Torben

 

[Boncuk]

The inductor appears to be part of a switching regulator circuit.
In the upper left hand corner of the entire PCB, there appears to be a burn mark near the screw. Have you lifted the board off and checked for burnt traces, etc on the flip side? I suspect you have more problems than just a burnt inductor.

The "burn mark" is a positioning pin for accurate PCB mounting. There is also one at the right hand bottom corner.

Don't lift the PCB unless you intend to pull out the digestionals. Check at FASTRON (ferrite core type PIS2408) for a suitable inductance. The printed value 3R3 points more to 330uH.

Boncuk

 

[rezer]

The "burn mark" is a positioning pin for accurate PCB mounting. There is also one at the right hand bottom corner.

Don't lift the PCB unless you intend to pull out the digestionals. Check at FASTRON (ferrite core type PIS2408) for a suitable inductance. The printed value 3R3 points more to 330uH.

Boncuk

It looks like a fiducial. There are 3 on the board. Upper left, bottom left and bottom right. These are used by the auto-placement machines to align the pcb for component placement. I just wanted to clarify. PCB mounts are usually tooling pins holes.

Also, the R in the value 3R3 is a decimal point. So InductorNoob is correct.

 

[kchriste]

It looks like a fiducial. There are 3 on the board. Upper left, bottom left and bottom right.

Ahhh. I see it now. It still looks a bit "burnt" on my monitor but it must just be the photo. I still think that InductorNoob is screwed and that there are other problems on the PCB. He'll be lucky to get off that easy.

Also, the R in the value 3R3 is a decimal point. So InductorNoob is correct.

I agree.

 

[rezer]

I still think that InductorNoob is screwed and that there are other problems on the PCB. He'll be lucky to get off that easy.

Yup, poor boy's got some problems. I feel for him (Unless he was in the bad habit of not making backups).

 

[Boncuk]

Also, the R in the value 3R3 is a decimal point. So InductorNoob is correct.

An assumption doesn't necessarily have to be the truth. Telling the R stands for a decimal point doesn't help much. Try to find an SMD-ferrite with an inductance of just 3.3µH. The size looks like it has to be 33µH.

The part doesn't look damaged. The OP could check for continuity before he orders a spare part.

Boncuk

 

[eblc1388]

This will, hopefully, remove one of the uncertainties.

 

[rezer]

An assumption doesn't necessarily have to be the truth. Telling the R stands for a decimal point doesn't help much. Try to find an SMD-ferrite with an inductance of just 3.3µH. The size looks like it has to be 33µH.

The part doesn't look damaged. The OP could check for continuity before he orders a spare part.

Boncuk

What do you mean? Are you saying I made an assumption or you did? I made no assumption. Telling someone that the R is a decimal point is the truth. How does this not help. It is the standard convention for component numbering.
Don't take it personal. Remember that the main purpose of this forum is to educate. Besides, he can't measure the 3.3uH inductor, it's missing. Read his first post.

 

[rezer]

InductorNoob,

I'm going to ask an obvious question. What happened to your inductor? Chances are, the regulator was over-driven and the inductor over-heated and fell of the pcb. Components can, at times, draw enough heat to melt the solder. I'm just curious if it's sitting inside your computer somewhere. We just have the "before" picture. Are there burn marks around the pads? I'm afraid you may have more damage, but it could be a simple matter of locating your inductor, meausuring it and putting it back on. Just a thought.

 

[Boncuk]

Besides, he can't measure the 3.3uH inductor, it's missing. Read his first post.

Believe it or not, I also read the first post.

According to the photo I can neither discover any missing part, nor any burnt spot on the PCB. I suspect the missing part did not evaporate.

The OP didn't clearly describe where the part was located.

Concerning an assumption it is one until it's proved.

L. Chung had the prove.

Boncuk

 

[rezer]

Concerning an assumption it is one until it's proved.

L. Chung had the prove.

Boncuk

That's true, but I made no assumption. What I said was accurate. People post all day long on this forum without giving proof for their opinion, and that's OK. But don't take what I say as the gospel truth. You can research it for yourself and if I happen to be wrong, then we both learned something.

 

[kchriste]

According to the photo I can neither discover any missing part, nor any burnt spot on the PCB. I suspect the missing part did not evaporate.
The OP didn't clearly describe where the part was located.

I was confused about that at the start too. My interpretation is that InductorNoob removed the inductor after taking the picture:

This is a close-up of the area which contains the (now missing) inductor:
**broken link removed**

I gotta admit that it's pretty cryptic.

 

[rezer]

According to his post, it was missing when he removed it from the bay after hooking up the wrong power. That's how I read it anyway. But one thing I haven't figured out is, why did he have a photo before it was damaged?