The client being a victim of a malefactor asked me to recover the information.
Seagate ST3120026A storage vol. 120 Gb contains valuable information. At power on the spindle engine is not accelerated. Diagnostics by means of technological socket connection reports about serviceability of printed circuit board and impossibility of plates acceleration to the necessary rotary speed. Installation of obviously serviceable printed circuit board leads to the same result. Check by special technique on possible spindle jamming which can interfere with plates acceleration does not lead to success as well; there is no jamming, and plates rotate freely.
I decided to test the engine winding on possible breakage though in practice such a problem happened extremely seldom, and the reason became clear at once even without an ohmmeter.
Conductors to the contact pad
External purposeful mechanical intervention was made to break the wire from the engine to the contact set. Conductors were sealed in plastic and embedded in the engine. To my regret, it was impossible to repair the store with such malfunction. Data recovery demanded to rearrange plates in the hermetical unit with the serviceable engine, and then to carry out procedure of plates package centering on specialized equipment.