Hd pcb repair of a burned component - Page 1
Forum section: electronics / beginners

author: Corvorosso610
author_rank: Newbie
timestamp: March 06, 2018, 09:40:40 am
content: Hi guysSorry to bother with my silly question, one of my very old hd burned out, after I plugged it on a Chinese transformer , as you can see from the picture the damage is not extended and I was thinking of repair the pcb, I found some used pcb but before changing it I wanna try to change that component.Now my question, I can't understand what is it all the sign are burned and is unreadable, I found an image of a complete pcb and seems a resistor r710 , seems correct for you ?Hd is a separate barracuda st3500830ace and the pcb serial is 100414872 rev aThank to everyone can help with thisPs sorry for my terrible English

author: capt bullshot
author_rank: Super Contributor
timestamp: March 06, 2018, 10:53:09 am
content: The burned component looks like a protection diode, usually a TVS. Under "normal" conditions it is an open circuit, for reverse polarity or overvoltage, it is intended to protect the rest of the PCB by limiting the voltage. Works to some extend, if enough energy is applied, it cannot protect the rest and the PCB has suffered other damage.There's an easy way to test the HDD PCB for further damage: just remove the diode and try to power up the HDD. If it works, search for a replacement, otherwise there's more damage

author: tpowell1830
author_rank: Frequent Contributor
timestamp: March 06, 2018, 12:23:14 pm
content: My first question would be: Why would you connect a hard drive to a transformer?Second question: Are you trying to repair this old hard drive because you have data that you don't want to lose, or is this strictly a learning endeavor?I agree with Capt Bullshot, remove burned device, clean PCB very well with acetone and make sure there are no shorts in burned area, and then power up using DC power supply with correct voltage/current rated to power up your hard drive. If it powers up, replace diode.Hope this helps...

author: Corvorosso610
author_rank: Newbie
timestamp: March 06, 2018, 01:18:57 pm
content: I want to repair it to learn more on electronics and for personal goal, there are some old data I like to recover but nothing critical.I was wrong not a transformer but one of that adaptor 12v from ide to usb. But I think has overcharged the component.I will try to remove the component and power up with a 12v and see if the hd power up.It's safer try with controlled power unit were i can monitor the current?

author: capt bullshot
author_rank: Super Contributor
timestamp: March 06, 2018, 01:33:27 pm
content: You'd have to apply 5V and 12V simultaneously. 12V alone won't work. Connect it to a suitable free HDD power connector inside a PC, that would be the safest way. Maybe you've plugged the USB/IDE adaptors power plug the wrong way in (yes with some force applied this works in some cases), that swapped 5V and 12V and destroyed the HDD. In this case, I'd expect the HDD to be completely dead.

author: Corvorosso610
author_rank: Newbie
timestamp: March 06, 2018, 02:33:33 pm
content: The chinese adaptor was plugged correctly, normally IDon't get wrong this simple task, also the adaptor burned aswell on the power pcb I didn't check were but I see a couple of components burned , so I bet the adaptor was overcharging the hd.I checked the motor and is ok and the rest of pcb even the under part is clean and don't show any sign of burning.

author: capt bullshot
author_rank: Super Contributor
timestamp: March 06, 2018, 02:51:26 pm
content: Then just carefully apply power to the HDD and see what happens. Overvoltage damage that already happened to the circuit may be invisible (except for the burned diode) and may cause more smoke now.You can either use a known good PC power supply, or a dual lab / bench power supply set to 5V and 12V, current limited at maybe 2A (the motor requires quite a bit of startup power). Just ensure to turn on the 5V and 12V at the same time. Don't hot plug the HDD power supply connector.