The head of the Stavropol affiliate of "Evrica" group of companies, one of 1C certified franchise over Stavropol region, came to me with his problem. One of their clients had a trouble with a luggable hard drive on which all the account data base were stored. I worked with that company on client data recovery.
In the USB 2.0 HDD External Box there was a Hitachi ATMR storage 2,5" vol. 40 Gb. At standard power on the engine accelerated and head position actuator evenly rapped against the stop.
During damage diagnosis defining I excluded disc microprogram bugs and printed circuit board failure that could lead to such rap. The only reason of it should be found inside the hermetical zone. I thought of either heads reading elements or preamplification/commutation chip.
Opened donor disc Hitachi ATMR
It is worth to mark such a peculiarity of notebook storage discs as plates scratching with bad heads. The matter is that head parking design features in all the range of hard drives 2,5" often lead to mechanical failure of reading /recording head holders.
In that case plates were good, I found a fitting donor disc at my repair shop store, and soon after head replacement all the necessary folders were sent to the file server.