The power input plug is loose in its socket. The printer is an Brother DCP 195C, and is working only when I wriggle the power supply plug where it connects to the printer, and the plug is properly engaged with its terminals, but the slightest touch on the power lead disconnects power and it does seem loose in its seat. I tried the printer in another room problem is still there so I assume its not the power cable.
What you have done is potentially dangerous. If the contact isd not perfect then sparking is possible and consequent fire risk. Get the socket replaced. A local computer repair store should do it for you.