To test the power switch, make sure the CPAP machine is unplugged and the top of the case is open.

To access the switch, you’ll need to temporarily detach the tube which is just above it.

Keeping the wires attached to the switch, push on the catches at the back of the power switch to release it from the front panel. Ease the switch a little way out through the front of the hole.

First, inspect the switch for any visible signs of damage. If so, assess whether it can be repaired with glue or solder.

Check that each metal connector is attached firmly onto a switch terminal. If any of these is loose or disconnected, this is probably why the CPAP isn’t working. Re-attach it and carefully turn on the machine to see if it now powers on.

Using a small screwdriver, slide each of the insulating sleeves slightly away from the switch. We need to expose a small part of each one of the metal connectors.

Next, let’s test the continuity of the switch using a multimeter. Set your multimeter to continuity mode. On this multimeter, it is indicated by a series of curved lines.

You can touch the prongs together to check what happens when there is a complete circuit. You should hear a continuous beeping sound and see a numerical reading.

Put the power switch in the OFF position. Press each of the multimeter probes against the terminals connecting to each brown wire – these are the live wires. Be careful not to touch the probes together or you’ll get a false result.

If the multimeter makes no sound and the screen displays ‘OL’, the switch is working correctly in the OFF position. If not, the power switch may be faulty and should be repaired or replaced.

Next, put the power switch into the ON position and again, place the probes against the terminals for the two brown live cables.
This time, if the multimeter makes a continuous beeping sound and the screen has a numerical reading, it means the switch is working correctly. If not, you’ll need to repair or replace the power switch.

If you’ve found that the switch is faulty and can’t be repaired, you’ll need to replace it with a new one.

You’ll need to disconnect the faulty switch. But first, take a photo or make a note of the positions of each of the wires.

Then, use a small screwdriver to slide each of the wire connectors off the switch terminals.

Attach the wire connectors firmly onto each terminal of the new switch. Follow the same positions as for the old switch. Make sure the insulating sleeves are pushed all the way over the connectors.

Click the new switch into the front panel, ensuring it is the right way up.

Then, firmly replace the tube above the switch inside the CPAP casing.

Fold the top panel back onto the machine and replace the screws.

Plug in the CPAP machine and try again to turn it on using the power switch.