The biggest danger from opening a piece of tech hardware (other than breaking it) is electrial shock. Equipment, especially older stuff, but really anything was designed to be plugged into the house mains may contain large capacitors in their power circuitry. These can store a surprising charge that would result in a major shock. Most modern equipment implements bleeder resistors that render them safe within minutes to an hour at most. Older equipment should be left unplugged for a day or three unless you know what you are about.

In particular older CRT monitors and TVs contain a flyback transformer circuit for the electron gun that runs thousands of volts and will hold a charge for a while (hours/days depending on the make and age).

The biggest danger from opening a piece of tech hardware (other than breaking it) is electrical shock. Equipment, especially older stuff, but really anything was designed to be plugged into the house mains may contain large capacitors in their power circuitry. These can store a surprising charge that would result in a major shock. Most modern equipment implements bleeder resistors that render them safe within minutes to an hour at most. Older equipment should be left unplugged for a day or three unless you know what you are about.

In particular older CRT monitors and TVs contain a flyback transformer circuit for the electron gun that runs thousands of volts and will hold a charge for a while (hours/days depending on the make and age).