Connect TX and RX ports with RS232 to TLL adapter, you'll need something like jumpers in order to do that, or soldering directly to the PCB board. Connect GND and +5V to PC power supply, or similar. Keep in mind those are direct from Seagate sides, so you'll need to connect in this way:
- From PC (TX) to >>> RX (on Seagate)
- From PC (RX) to >>> TX (on Seagate)
You can use RED wire (+5V) from PC power supply. Blacks are GNDs (yellow is +12V so don't use it).
If you don't want to mess with power supply, just use a CR2032 (3V) battery: