Samsung HD501LJ dead, a year of work in risk!!!

[salamelevrai]

12V seems ok too.

Then it means that I don't have shorts.

Still, I can clearly see that the jumper exploded or burned or something..

To sum up, if I understood correctly the previous posts, I have to remove the jumper, put a fuse instead with different amp spec and see how it reacts ?

[dayslypper]

First tell me what is the resistance of jumper with low range of resistivity?

[salamelevrai]

Well, unless I misunderstood something, the reading of the resistance on the jumper is 1365. When you say : it should have low unmeasurable value, it means that the multimeter should show 0 or near 0 ? or on the contrary, very high value ?

sorry for the probably stupid questions.. I'm not much at ease with electronics.. !

Hello people,

I tested my PCU for shorts around the 2 TVS and the jumper.

I read the following values (calibre 2000kohms)

jumper : 1365
TVS 5V : I read 1
TVS 12V : 43

[dayslypper]

Simply, it should displays quite the same value as it displays if you connect both electrodes of multimeter directly (without any tested part in electrical circuit).

But if you want to know what you measure than you should to refill knowledge about voltage, resistance, current and their fundamental features whose are teached in primary or secondary school.

You can read:
http://en.wikipedia.org/wiki/Electrical_resistance
http://en.wikipedia.org/wiki/Voltage
http://en.wikipedia.org/wiki/Transient_ ... sion_diode

[misiu_mp]

Hello people,

I tested my PCU for shorts around the 2 TVS and the jumper.

I read the following values (calibre 2000kohms)

jumper : 1365
TVS 5V : I read 1
TVS 12V : 43

With multimeter set at 2000kohms, reading of 1365 means 1.365Mohms, which means the jumper is fried.

[dayslypper]

Jumper can be perceived like classic fuse:

No resistance = OK, Inf. resistance = burned

So I can say that jumper have inverse atttributes than TVS.

[misiu_mp]

I haven't read through all the suggestions, but when I have a blown board, I do not try to fix it because of the simple reason that many other IC's are also blown when the "fuse" blew. The fuse acts too slow to prevent the other components from being damaged!

The only jub of this fuse is to prevent fire on the board! I had this happen many times in the last 20 years in the PC business.

The good intentions of others are admirable, but all the help they suggest will just lead to frustration and maybe loss of all data after you think you have the correct component.
The only practical and only real solution is to buy another identical knows working drive (ebay, craigs list, etc.) and swap the board.
Sometimes this didn't fix the problem either, because there is a read/write head pre-amp inside the drive itself which was also blown. This is another tiny circuit board with electronics on it inside the cover. There's no way you can replace this yourself.
If you try another board and it doesn't work, your only solution is to send it to someone that specializes in data recovery. The actually remove the platters in a clean room environment and install it in a known good drive to recover the data.
Trust me, fooling around with replacing components is useless. I've been there and done that many times, and never was able to fix a board. Swapping it with a know good one is the only solution.

It is not the fuse that protects the circuits, its the TVS. And it is blazingly fast.

Look what I found: http://www.semtech.com/pc/downloadDocument.do?id=509 (pdf)
It says there that TVS are designed to short-circuit at a certain voltage keeping the voltage over the protected element at that limit.
They work extremely fast so you can stay assured, when they worked, the PCB and all the chips on it did not get overvolted and fried.
The fact that it takes a while for the jumper to blow doesnt affect that. All the time the jumper heats up before it blows, the TVS keeps the current flowing through itself, protecting the vital circuits. The jumper's role is to blow before the TVS does.

Pretty neat, eh?

Of course this protects the drive mostly only from external over-voltage, such as a surge, a faulty psu, or mixing up the 12 and 5 volt lines.
Its a different matter if the fault happens inside the 'safe zone' protected by the TVS.

[salamelevrai]

Hi folks,

Just a big thks to everybody who has participated into this topic. I solved my problem by putting a strap over the jumper. I was able to recover all my data. The drive is actually still working, but I intend to throw it away.

I will be posting a picture of the drive soon, in case it helps some other people.

Thks again

[chrisi99]

Sorry for ressurecting this old topic, but I found this page because I desperately searched for a way to rescue my HD501LJ from sudden "PCB-Death".

Here is the diagnostic finding:

Disc was always cooled well by 2 ventilators, worked fine until yesterday evening where it all the sudden stopped working at all. Means no spinning up when connected to the PSU, other drives work fine.

unfortunately (to say so ^^) nothing is burned so obvious as in some of the pictures.

using a multimeter i found out, that the motor gets no current, therefore something _must_ be burned.

how can I test the pcb to find out, what is wrong?

the "bridge" (Zero Ohm resistor) has 108kOhm, so that one seems to be burned for sure.

How can I test the TVSs? one shows around 50kOhm, the other around 600Ohm... could that be ok?

hope someone is still whatching this

best regards
Chris

[r3712]

It sounds old like a world. But again. If your data is valuable for you - let pro do it. Trust me - it will be the best solution.

[dayslypper]

I tkink that it depends on polarity of measuring TVS.

You could try to measure it with oposite electrides of multimeter but I'm think that maesuring of resistance of TVS can cause damage of TVS in good condition. (e.g. if you measure 5V TVS with multimeter with 9V battery.

Try to unsolder TVS which is in circuit with burned Zero rezistor and than try to run HDD.

P.S.: Please, solder with soldering station but NOT with soldering gun!!!!!

[chrisi99]

Hi dayslypper!

thanks for your reply!

Do you mean solder the TVSs out and short curcuit them with a wire?

I have all sorts of equipment from my workplace at the university, so a soldering station is no problem =))

best regards

[dayslypper]

Do you mean solder the TVSs out and short curcuit them with a wire?

NOOOOO! Only remove TVS! Please, read something about aplication of TVS first.

If you haven't solder station, then you can try one methor, I did it with my HDD but it's quite risky and I could not recommend it: Take pliers and break off the top of TVS. I mean top half of epoxide shell. After that you will able to divide electrodes of TVS. But remember that you risk damage of PCB.

[fzabkar]

I'm think that maesuring of resistance of TVS can cause damage of TVS in good condition. (e.g. if you measure 5V TVS with multimeter with 9V battery.

Take pliers and break off the top of TVS.

ROTFLMAO.

Please tell us that you are not a pro.

If you claim to be one, then please read a TVS diode datasheet ... any TVS diode datasheet.

Then ask yourself, how much current does a multimeter, whether 9V or less, deliver into a short circuit? If you don't know, then set your DMM on the lowest ohm range (or diode range) and plug the two probes into the amp terminals of a second DMM. And while you're at it, measure the open circuit voltage by setting DMM #2 to the 10V range. You will probably measure 1mA and 3V, respectively.

You may also want to ask yourself, how much current does a 12V power supply deliver to a TVS diode with a 12V working voltage?

BTW, I suggest that the OP use side cutters, not pliers, if a soldering iron is unavaliable. You wouldn't want to risk lifting any pads or tracks.

[dayslypper]

I'm amateur. I would to try it, before I worte it but I had no second multimeter. Sorry for this bullshit.

BTW, I suggest that the OP use side cutters, not pliers, if a soldering iron is unavaliable. You wouldn't want to risk lifting any pads or tracks.

I hadn't side cutters at that time. I know they would be better.

[fzabkar]

I'm amateur. I would to try it, before I worte it but I had no second multimeter.

Now I feel like crap. Please accept my apology.

In fact, I'm not even a DR amateur, so you're a step ahead of me. Just call it a brain fart and forget it. I've had plenty of them.

Actually, from what I've seen, I'm betting that you may have a better understanding of electronics than most of the DR pros.

Cheers.

[ChosenWon]

Just adding an update with links to better pictures. I see this is a common issue with samsung drives, and have found that it is somewhat similar to the seagate drives as well:

Most of the people who are posting solutions such as "Remove TVS" are actually professional data recovery technicians who enjoy helping out a little in their free time. I am a DR tech for a small Socal based company and I can say that removing a TVS is not big issue at all as long as you make sure your power source is secure, and you are only running the drive long enough to extract the valuable data.

I did this exactly and it worked well. See my thread with close up pics here:

specs-and-pics-just-need-yes-advice-please-help-t15153.html#p99092

BTW I am now a big fan of the heatgun 'reflowing' technique. Especially if you are under warranty. As you can see earlier in this thread a soldering iron will leave obvious scorch marks, but the heatgun IF use properly can be nearly imperceptible ... at least imperceptible to the guy looking over the drive at the warranty dump station anyway.

BTW With my seagate, I only had to remove the TVS diode, and did not have to do anything with any fuses.

And another big thank you to the experts on here that contribute to help us little people.

-Michael

[tvsgone]

Most of the people who are posting solutions such as "Remove TVS" are actually professional data recovery technicians who enjoy helping out alittle in their free time. I am a DR tech for a small Socal based company and I can say that removing a TVS is not big issue at all as long as you make sure your power source is secure, and you are only running the drive long enough to extract the valuable data.

I agree. There's a lot of nonsense mentioned in this thread but removing the TVS is okay.

I aquired a friends HD501LJ with the diagnosis that he plugged a 19V laptop supply into the LaCie caddy that contained the Samsung HD501LJ.

After reading up I measured the resistance of the zero-ohm resistor = ~0 ohms, the 5V TVS = infinity, and then found that the 12V TVS measured 2 ohms in either direction, this was the culprit for the drive not spinning-up.

Next step was to remove this with a soldering iron. After doing this connected it up and it worked fine.

Copied the data off, aim to replace the 12V TVS.

Thanks to everyone who posted something sensible.