Which case should i remove ?

I dont have a voltmeter so i cant measure the values.

fzabkar, Does the HD103UJ use the same PCB ? Do you know that ?

The drives belong to different families, EcoGreen F2 versus SpinPoint F1. In any case you would need to transfer the firmware from one PCB to the other.

A digital multimeter costs US$5, or less, on eBay.

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A backup a day keeps DR away.

Hello Guys,

I have two bad HD154UI. The power lines of my CM case's HDD bay were swapped. so both of them got 12V to their 5V line. I have checked the diodes, they have a couple of MOhm resistance, I assumed they are fine. I have also checked the fuse next to the 5V diode, it has a few Ohms, so it seems fine too. I have made the measurements, fzabkar proposed.
Please help!

Thanks,
zsedro

@zsedro, your voltage measurements would suggest that there is a problem with your PSU, the 5V fuse, or your measurement technique.

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A backup a day keeps DR away.

@fzabkar, first, I had measured with an external sata-usb adapter, which has its own psu, now, I did a similar measurement with my pc's psu and also with another mutlimeter. I have got similar results. I have got everything you showed (the sata pinout:gnd-5v-gdn-12v), but not the 5v at the diode. I used a screw as ground and I measured at the small holes and also at the leg of the diode. Can it be the capacitor, or can it be the 5v diode? What is your suggestion?

The "fuse" must be open or high resistance.

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A backup a day keeps DR away.

You mean this spot (circled)? I measured closed in between the two holes connected with the line on the image.

There cannot be a potential difference across a short.

Perhaps the "fuse" is a resettable type that returns to zero ohms after power is removed?

Could there be a "dynamic" overload? What is the resistance between ground and each of the Vio and Vcore test points (at the coils)?

Are you testing the PCB off the drive (preferable)?

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A backup a day keeps DR away.

You are absolutely right, sorry. The "short" was 140 Ohms and 70 Ohms for the two drives (measured with the fixed range multimeter @200), I was just stupid enough to use my multimeter's short circuit detector feature. I was measuring everything up until now with the board on the drive. At the coils, I measured 1.2 KOhms and 60 Ohms to the ground.

A load resistance of 60 ohms is probably OK for the Vcore supply. I'm surprised that the 5V TVS diodes survived after the fuses were stressed. Good luck with the repairs.

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A backup a day keeps DR away.

Thank you very much fzabkar! I did the fix today (I have put a blob on the fuses), and it works like a charm! God bless you, man! It could have taken weeks and $500 to ask a company to fix this problem for me. Do you have any paypal, or any page, where people can donate you?

Congratulations. Thanks for you kind offer, but I don't accept donations.

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A backup a day keeps DR away.

I have read the items in this forum and it is close to some of the questions that I have. I am having problems with a Samsung HD103SJ that seems to spin up but it is not recognized by the PC. I was told that I may need to replace the Transit Voltage Suppressor (TVS) on the PCB. I was glad to see one of the responses from user fzabkar about part number SMBJ12A for the 12V TVS and SMAJ5.0A for the 5V TVS. Evidently, the HD154UI is very similar with the HD103SJ including the printed circuit board so I followed some of the directions about measurements. From all the parts I measured, they appear to return valid information. I have not found any missing or damaged parts. I have also read up on replacing the PCB and BIOS. Any suggestions or associated links will be greatly appreciated.

If the drive spins up, then the TVS diodes are OK.

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A backup a day keeps DR away.

Thank you for your answer! At least I don't have to worry about the TVS parts. So the next question is, what steps do I take now to try to get the computer to recognize the drive?

Start with a diagnostic report.

How to connect a terminal adaptor on a Samsung drive ?

https://www.hddoracle.com/viewtopic.php?f=116&t=189

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A backup a day keeps DR away.

Okay, thanks for the previous answers but I have a few more questions. Assume I am able to connect to the drive using the serial port, how do I ask for a diagnostic report and what am I looking for on that report? I have tried most of the suggestions presented by other users but still, I have not received a positive outcome. My next thought was to replace the PCB on the hard drive. The part number for that PCB is BF41-00303A but I have not been able to find a supplier because they all say they are "out of stock". Does anyone know where I can order that PCB? It appears that the BIOS can be swapped from the original PCB to the new one making the new one work like the old one. After checking with a Data Recovery company, the recovery cost is out of my budget. I am still open to suggestions. Thanks!

The drive will output diagnostic info of its own accord. The next step depends on what you see.

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A backup a day keeps DR away.

Thank you! I will see what it says.

Do you possibly have any suggestions on the PCB supplier?