While re-wiring my KVM (old 2-port sat below the desk and was remotely operated, new 4-port sits above desk) I had to disturb various cabling, including a 6-way mains strip ... while doing that I heard a nasty BZZZZT! arcing from inside it.
Went to open it up, using snake eye security bit, and one of the 'teeth' broke off straight away, I suspect the bit was one of those from a set of 76 bits you have to buy when there's just one you actually need, so ordered a decent set of snake eye bits.
Anyway managed to open the 4-way with a wrong sized snake eye bit, I know some multiway strips are surprisingly cheaply made, this one more than normal, three zig-zag brass strips, not even spot welded to the contacts the plugs go into, just wedged in contact between the contacts and bits of plastic. The arcing was related to the neon+dropper resistor, so I just cut it out.
Anyway, rejigging all the the cabling wasn't too expensive, I could re-use some of the DisplayPort cables, others needed replacing 2m to 3m, others replacing 1m to 0.5m, to suit the new arrangement, some got upgraded from USB2 to USB3 in the process.
Also bought a couple of active adapters so the spare KVM port can now handle HDMI or VGA connection for "visiting" computers, even mini-HDMI for the rPi Zero.