Recently, TS120GSJ18M had started to turn off on a high-load (data transfer). After several failed tries to copy large files (>4 GB) it had been disassembled and inspected:
Inside the case: The circuit-board based on the JM20335 LGAA1C chip (USB to PATA bridge) connected to the MK1231GAL drive (ZIF socket).
The board testing revealed no issues.
The assumption in a cable’s issue – the flexible flat cable was flipped upside down and the HDD works great now.