I recently started having problems with my lathe failing to turn on. Sometimes tapping the area around the switch would work but eventually I had no power at all. The problem was how to get at the back of the switch to test it or by-pass it. The switch does go in through the front and has a barb connection at the bottom of it but the wires are so short you cannot pull the switch out far enough to pull the slip on terminals off. To save someone from going through what I did as to how to get the control box off to get at the wiring I will share what you need to do.
If it's a table top, no problem, just take the two screws off the right side of the box and lift up the tail stock side of the lathe and the box drops down and comes off. If yours is on a stand like mine it's a lot harder! You must remove the stand and move the lathe bed up far enough to allow the control box to pulled down and out. Once the box is out you have access to everything. It turners out that my ON/Off switch was full of powered saw dust. The switch is well made with a rubber boot inside to prevent this from happening but it did anyway. I had to drill the rivet out to take the switch apart so it could not be re-used and it was worn from use anyway so I ordered a replacement for around 12 bucks. I also made some extension wired so that if it happens again I will be able to replace the switch from the front. There are two button head screws on the from of the bezel but they hold the readout assemble and have a nut behind it. Don't turn these unless you have the control box out and need to replace the readout assemble. Hope this helps someone.