Seagate ST3500312CS Overvoltage Damage - Page 1
Forum section: electronics / beginners

author: 2X
author_rank: Frequent Contributor
timestamp: September 05, 2023, 07:21:34 pm
content: Hello,I have a Seagate ST3500312CS where is dead because overvoltage of the power supply. When I unscrew the PCB I saw that three capacitors (or maybe ferrite beads) where blown out. Do you have any idea if I have a possibility to fix it. The problem is that I have an industrial custom PC where recognizes only the disk with thecertain only firmware(it is crazy but it is true). Does anyone know where the firmware of the disk is saved (I have another Segate disk but with different firmware and I thought If I could replace the firmware chip in the good one). Anyway, I would like to fix it (always there is something new to know in repairs), so there is any schematic of HDDs or what to suggest me to check it will be very helpful?P.S. I hope I didn't post on the wrong thread.

author: delvo
author_rank: Contributor
timestamp: September 05, 2023, 08:59:49 pm
content: I dont think this is going to work. That chip will also have calbration data for the disks. You cant transfer it to a different drive

author: Manul
author_rank: Super Contributor
timestamp: September 05, 2023, 09:03:13 pm
content: Are you sure that PC requires certain only firmware? Can it be serial number lock? Back in the day I used hdd serial number lock for some of my software.Anyway, the firmware may be stored together with head calibration data, so I would say switching chips, even for exactly same model is unlikely to work. If the model differs, it's even less chance. That's my opinion.If 12V rail is the only one which suffered, the best aproach would be to try repairing. First I would measure the rail for shorts. Maybe the board is still ok. Or maybe you will find that motor driver IC or something else simple is damaged. These should not be hard to replace, and it has nothing to do with calibration (as far as I know).

author: 2X
author_rank: Frequent Contributor
timestamp: September 05, 2023, 09:07:52 pm
content: Quote from: Manul on September 05, 2023, 09:03:13 pmI will try to repair it and not to risk it... by the way which chip contains the calibration data/firmware? Also, these three components that blown out do you believe are capacitors of ferrite beads?

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 05, 2023, 09:08:32 pm
content: Take the original board and remove the TVS diodes. They usually short out protecting the rest of the board.Removing them will tell if there's permanent damage. The ferrite beads can be shorted out for the test, better put a 1-2Amp fuse or a 0 ohm SMD resistor.Also, I've repaired several disks by transferring the original eeprom chip to the new donor board.Make closer pictures of these parts.

author: Manul
author_rank: Super Contributor
timestamp: September 05, 2023, 09:22:54 pm
content: Quote from: 2X on September 05, 2023, 09:07:52 pmI guess firmware is in one of these SO8 packages. SPI flash. Not sure and can't read from picture. The three components should be ferrite beads. It's easy to check with multimeter, if they go in series with supply, they are ferrite beads.

author: 2X
author_rank: Frequent Contributor
timestamp: September 05, 2023, 09:41:52 pm
content: I found the one from the SMD code that is maybe Transient Voltage Suppressor. The one soic chip is "25X40CL" and the other one is "NTMD4184PF" I beleive (MOSFET – Power, Single, P-Channel, Schottky Diode, Schottky Barrier Diode). I wll measure all the components that you told me and power supplies and I will tell you the results.QA NSA5.0AT3G SMA 2 400W Peak Power Zener Transient Voltage Suppressorhttp://markingcodes.com/search/c/QA25X40CLhttps://datasheetspdf.com/pdf-file/1315797/Winbond/W25X40CL/1NTMD4184PFhttps://www.onsemi.com/pdf/datasheet/ntmd4184pf-d.pdf

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 05, 2023, 10:18:55 pm
content: You missed the other large diode!What do they measure in diode mode?

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 05:17:31 pm
content: Quote from: DavidAlfa on September 05, 2023, 10:18:55 pmYou were totally right. I first I measured the "pE49 LEK" and was short... I desoldered and I measured it on the fly again and it was short and also the short from the PCB was gone. Then I measure one other smd component at the side of the sata power connector from another Seagate disk and it was a ferrite bead. I put instead of ferrite bead 1.5Ω resistors and the disk works fine and the machine too. Because I want to repair it as it was, I would like your opinion about what components were the originals.Resistor: thick film; SMD; 0603; 1.5Ω; 0.1W; ±1%; -55÷155°CManufacturer part number: RC0603FR-071R5Lhttps://www.tme.eu/en/details/rc0603fr-071r5/smd-resistors/yageo/rc0603fr-071r5l/The good ferrite bead I measured it with keysight U1733C and it shows inductance 1.7uH (I don't find a ferrite bead with inductance characteristic on sites - it is something wrong?) and resistance 1.21ohm. The Seagate disk draw 0.155A @ 12V. Because 0.155A will not flow only through a bead but will divide through three beads. Ibead=0.155A/3=0.052A(ideally that the current is divided equally), so 1.5x0.052A~0.078A=78mA (I found at 100mA).Part Number: BLM18HD471SN1Dhttps://gr.mouser.com/ProductDetail/Murata-Electronics/BLM18HD471SN1D?qs=WYZ1yQOz%2FLFGae%2Fi4Y5yJw%3D%3DThe "pE49 LEK" I found on the below site that propably is this part number "NSB12ANT3G"http://markingcodes.com/search/c/LEKhttps://datasheetspdf.com/pdf-file/691810/ONSemiconductor/NSB12ANT3G/1The below is a good choice for replacement?Part Number: SZ1SMB12AT3Ghttps://gr.mouser.com/ProductDetail/Littelfuse/SZ1SMB12AT3G?qs=sK5eIuwOod4%2Fto4W2E8Wrw%3D%3DThanks you and the other guys for the help.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 06, 2023, 06:13:51 pm
content: Quote from: 2X on September 06, 2023, 05:17:31 pmThe code is "LEK", forget the rest.Quick answer from:https://community.wd.com/t/hdd-tvs-diode-faq/14692QuoteQuote from: 2X on September 06, 2023, 05:17:31 pmYeah but it will be a lot more at spin-up! But if it's working with 3x 1.5R resistors, I guess it will also work with 3x 1.28R chokes.I'd try to find others with lower resistance, though.

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 06:39:40 pm
content: Quote from: DavidAlfa on September 06, 2023, 06:13:51 pmThe inductance doesn't play a role? With what resistance would you recomend to find a ferrite bead?https://gr.mouser.com/c/passive-components/emi-filters-emi-suppression/ferrites/ferrite-beads/?package%20%2F%20case=0603%20%281608%20metric%29

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 06, 2023, 07:58:50 pm
content: It's not a switching converter, here the inductance simply acts as a filter for high frequency noise.The higher the better, but keeping DC resistance low.BLM18KG102SN1Dseems a good candidate, 1Amp rating, 0.1Ohms at DC but 1K impedance @100MHz.Xc of 1.7uH at 100MHz is 1068 Ohms. So it seems to match.Personally? I would leave as it is. It's a 500GB mechanical drive, probably has more than 10 years.Between parts and shipping cost it'll be half of a new drive!

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 08:14:48 pm
content: Quote from: DavidAlfa on September 06, 2023, 07:58:50 pm

author: u666sa
author_rank: Frequent Contributor
timestamp: September 06, 2023, 08:18:34 pm
content: They are protection diodes. You can replace them with 0 ohm or jump with solder.But before you do test for short circuit. If no short circuit proceed as above. If there is short circuit, find what is shorted.You should give it a thorough inspection under microscope with multimeter in diode mode. Beware, if you screw up, you won't recover your data. So if it's important, send it reputable repair shop and pay money to get it fixed -- NorthridgeFix for example.

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 08:24:46 pm
content: Quote from: u666sa on September 06, 2023, 08:18:34 pmI repaired already and work fine.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 06, 2023, 08:28:11 pm
content: Quote from: 2X on September 06, 2023, 08:14:48 pmI mean a new drive - any new drive. Why it does to be the same drive and FW?Is it for a special machine with license locked to the HDD? In that case, the money in repairing an old drive is totally justified.

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 08:32:40 pm
content: Quote from: DavidAlfa on September 06, 2023, 08:28:11 pmIs a PC based machine and it for some reason it checks the disk firmware in order to live you to install the image.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 06, 2023, 08:49:03 pm
content: Yeah, I suspected so when you kept saying it must had the same firmware.I had similar repairs in the past, 2000s or even 90s machines which costed millions when new.Thus they didn't care if a 128MB RAM stick was $100, they just wanted it back to service YESTERDAY.

author: 2X
author_rank: Frequent Contributor
timestamp: September 06, 2023, 08:52:11 pm
content: Quote from: DavidAlfa on September 06, 2023, 08:49:03 pmYou truly understand me.

author: amyk
author_rank: Super Contributor
timestamp: September 07, 2023, 02:29:01 am
content: I recommend finding a way around the software/firmware lock. Regardless if you manage to get the disk fixed.

author: 2X
author_rank: Frequent Contributor
timestamp: September 16, 2023, 11:45:44 pm
content: Quote from: amyk on September 07, 2023, 02:29:01 amAlso,I made a disk by replaced the SH6964B TI Motor Controller (tested and works fine).