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pcdata76
November 5th, 2017, 06:10 AM
I've owned a late-model 5160 with original Xebec MFM controller and IBM full height 20MB hard drive few months ago. Power supply was dead, so i've transplanted the board of an ATX power supply into the case of 5160 PS. I've powered it on but a tantalum at the 12V rail on CGA card went short circuit and smoked to death. After replacing it with an electrolytic, it powered-on but hard drive was making strange seek noise after spin-up. I've booted from floppy, did some tests using spin rite and failed at seek test.

After some inspection, i've identified a physically burned transistor on the PCB of the hard drive, which is responsible of controlling head stepper braking solenoid. PCB and nearby resistor also have some heat damage. Wrap around the solenoid coil is also melted due to overheat.

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Instead of replacing the transistor, patching the damaged PCB tracks and identifying the other possible faulty components, i've decided to remove the solenoid entirely off the drive :D Stepper motor shaft is stiff enough to not move even without a braking solenoid so i don't think it is bad to remove. After the removal of the solenoid, drive came to the life and seeks perfect.