Before you open a machine

⚠ Safety guide. This page covers hazards that can cause serious injury or death. Read it fully before you start, and if you're unsure, stop and ask someone experienced.

{| class="wikitable" style="float:right; clear:right; margin:0 0 1em 1em; width:280px;"

! colspan="2" style="text-align:center;" | Guide details |- ! Topic | Safety |- ! Applies to | Both |- ! Difficulty | Easy |- ! How often | — |- ! Tools needed | Flashlight
Safety glasses
Multimeter |} Read this before you open any arcade cabinet or pinball machine, every time.

The basic rules

1. Unplug it. Pull the plug from the wall. Turning off the switch is not enough, because many machines have live wiring before the switch.
2. Keep the plug where you can see it, so nobody plugs it back in while you're working.
3. Wait a few minutes after unplugging. Some parts store energy after power is removed (see CRT monitor safety and Mains power safety).
4. Wear safety glasses. Springs, clips, solder, and glass can fly.
5. Take off rings, watches, and metal bracelets. They conduct electricity and can catch on moving parts.
6. Work in good light, with room to move and a clear floor.
7. Don't work alone on monitors or anything high voltage. Someone nearby can unplug the machine and call for help if something goes wrong.

Take photos first

Before you unplug any connector or remove any part, take a photo. Photos of connectors, wire colors, and part orientation will save you hours when you put it back together.

When the machine has to be on

Some troubleshooting needs power, like checking voltages with a multimeter.

• Keep one hand in your pocket or behind your back when probing live circuits. That way current can't cross your chest from one hand to the other.
• Know where the high-voltage areas are (monitor, power supply, line filter, and on pinball machines, the display and coil circuits) and stay clear of them.
• Don't reach across the machine or lean on the cabinet while it's powered.

Isolation transformers

Many arcade monitors are "hot chassis," which means the metal frame of the monitor can be connected directly to wall power. Most arcade cabinets include an isolation transformer for the monitor to make this safer.

• Never remove or bypass the cabinet's isolation transformer.
• If you power a monitor on the bench, use an isolation transformer there too.

Stop if you're not sure

If something looks burnt, smells hot, or doesn't match what a guide describes, stop and ask on the wiki or a repair forum before going further.