Be Safe
Electricity
ELECTRICITY CAN KILL. First and foremost, make sure the washer is unplugged. If your washer has a big power switch on the front, don’t just turn that off and think that’ll do. If the washer is plugged in, then there are still some parts that are live.Check that the thing you have unplugged is definitely the washer. Unplugging the toaster may result in the washer taking its place and you becoming the toast. If necessary follow the lead from the washer back to the socket. If there was some visible sign of life in the washer before you unplugged it, make sure that has now gone out.
Don't trust anyone else to unplug the appliance. It's you that will be lying in the ground.
Repeatedly plugging and unplugging the washer to test while working on it is dangerous. It is very easy to get distracted in the rush/frustration to get back to it and forget. Never leave the washing machine unattended while it is plugged in with live parts exposed. This could come as a real shock to someone inadvertently passing.
Be careful if you bypass any safety mechanism for diagnostic purposes. They are they for a reason, and disabling them can introduce new problems. I know one person who put aluminium foil around the fuse to stop it blowing. The result? The circuit board blew. Always make sure they are back in place when you have finished.
Moving the Washing Machine
Before you start to move the washer, check how long the pipes are. Make sure they are long enough for you to pull it out with out stretching or breaking them. It's hard enough to repair the washer without having to do a spot of plumbing as well. If the pipes aren't long enough, disconnect them. Of course, turn off the isolation valves first, then place the pipes into a bowl or other container to catch any water still in them.Other Hazards
Inside a washing machine there are lot of sharp corners and pointy metal bits. Be careful trying to undo that troublesome screw. A slip of the hand can result in a very nasty cut.Never turn the washing machine completely upside down. The suspension for the drum is not designed to work that way. You can gain to the underside by laying the washing machine on its side.