Good evening,
I originally asked this question in the ST forums, and was referred here by a helpful individual's response. I'm tinkering with an old WD400BB hard drive that I'd presumed was a lost cause, but carried it around in case I ever got the itch to try to fix it. It's become a mystery/challenge that I'd love to solve, but if I lose it, then it's zero loss!
Problem: The original symptom was that the hard drive fails to spin up at all. No sound, nothing. I purchased a donor PCB just to test with, and discovered that it too cannot power up the drive. At this point, I assumed it was a dead motor/something physically wrong, so as a last ditch effort I took a PCB from a completely different model and connected just the 4-pin motor assembly to the pads, and was surprised to hear it spin up. Two PCB's with the same symptom seemed like a long shot? I'd hate to order yet another one just to find out it is something else...
What I've tried:
Would love any guidance/thoughts from anyone, and I'm happy to test/provide additional information if needed. I saw another user's post about a similar issue that was solved by bypassing a resistor. I can't find a resistor that's bad, so I wonder if something else might be going on.
Thank you!
I originally asked this question in the ST forums, and was referred here by a helpful individual's response. I'm tinkering with an old WD400BB hard drive that I'd presumed was a lost cause, but carried it around in case I ever got the itch to try to fix it. It's become a mystery/challenge that I'd love to solve, but if I lose it, then it's zero loss!
Problem: The original symptom was that the hard drive fails to spin up at all. No sound, nothing. I purchased a donor PCB just to test with, and discovered that it too cannot power up the drive. At this point, I assumed it was a dead motor/something physically wrong, so as a last ditch effort I took a PCB from a completely different model and connected just the 4-pin motor assembly to the pads, and was surprised to hear it spin up. Two PCB's with the same symptom seemed like a long shot? I'd hate to order yet another one just to find out it is something else...
What I've tried:
- I've tested as many components on the board as possible, especially those that seem like they're on the pathway to the motor interface.
- I think I've hit every resistor and they all seem like they're within range (but I could be wrong, as I'm learning my way through this in this project)
- My original post on the ST forum helped me understand that the ST L6262 2.6 chip was custom made for WD, so there are no publicly available datasheets that would tell me if the motor IC voltages are expected, or what the pins are even used for.
- I've attached the voltage readings on the motor controller, along with green lines indicating good continuity tests between the 4-pin interface and the chip. I assume these are OUT_A/B/C plus a ground, but as you can see none register any output which explains why the drive motor doesn't spin up.
Would love any guidance/thoughts from anyone, and I'm happy to test/provide additional information if needed. I saw another user's post about a similar issue that was solved by bypassing a resistor. I can't find a resistor that's bad, so I wonder if something else might be going on.
Thank you!