The "dead" driveMark B., 2019-03-18 17:58
A client send us a "dead" drive which don't spin up. While inspecting the PCB with the microsoce we saw some small burnmarks which indicate a faulty PCB. To crosscheck our diagnose before we search an donor we hook the drive with a similiar PCB up and it come back alive.
Now we know we are on the right way and we contacted our suppliers to find a matching donor-drive within the closest possible margin of production-date form the same factory, with the same revision of the printed circuit board and the same version of the firmware. Then we ordered the best matching one from Portugal and wait for it's arrival.
After the donor arrived we had to desolder and transfer the ROM-chip from the patient to the donor PCB and reconnect the printed circuit board with the drive. When we start imaging the drive we saw that was not the only problem - one of the heads where reading very slow so we dicided to create a headmap and go for the easy accessable data first. After we had 75% of the data saved we started to work on the bad read-write-head. First we read the data with a slower DMA-mode and we skipped a few blocks when hitting a problematic sector - that give us quite some data without stressing the drive to much.
To overcome some possible buffer issues we fill in all missing gaps with a reversed imaging pass and yet another reading mode sector by sector which leave us with just some bad sectors left. As the majority of the data, more then 96% in that case, where save on our fileserver we started the last pass with multiple retrys of bad sectors to get the last bit's and bytes. After the drive start to rapidly decrease in heath we stopped the process and created a file-report for the client.
Thanks to carefully imaging and getting the lower hanging fruits first with spezialized tools we could read more then 97% of the data bevore the drive was so bad that he would need a threatment in a cleanroom. As all of the missing data where located in the programms- and windows-folder. So the client got all his wanted data back without any expensive cleanroon threatment.