The motorized volume control on my NAD C340 integrated amp stopped working. After reading some advice here, I checked the connection inside from the main circuit board to the small board containing motorized volume and tone controls. I played with the 6 wire ribbon connection a bit and the motorized volume started to work but I lost the left channel. The 6 wire ribbon seems to have bare wires that push into a socket on the main board. How do I remove the ribbon from this socket to clean the bare ends to get a better connection?

Audio Players & Recorders - NAD - C350 2-Channel Amplifier