how can I fix my dyson DC04?

Sound like you may have abreak in the cable as it enters the dyson (Common Fault) you can get to the cable by removing the switch you require a sharp small screwdriver and gently pus it in to the flat bit oo the switch (nearest the wand) and this will release the snaplock and using a pair of pliers remove the switch button. you will need a tork screwdriver to remove the switch train this will allow you to get a t the cable.
if the motor was varying in speed and noise this sounds like a new motor ?
hope this helps

Tickityboo (the Dyson Man)
June 2011