Hoover Nextra error 7 (as with all Nextra error codes) is shown by flashing two lights in a 15 second cycle, usually the start and pause, or start and delay-start leds. If you count how many times the lights flash before pausing and repeating the sequence and it amounts to 7 flashes then this page explains the meaning.
Nextra error code 7 means –
“Motor jammed / Drum shaft jammed / Tacho generator fault”
Remember error codes are specific to one make or even one range of washing machines. An error 7 on an AEG for example will mean something different. These three explanations all refer to a specific fault where the washing machine knows it’s supplying power to the motor and that the power is running all the way through the motor and back to the main pcb. Therefore it knows the motor should be running – but it cannot detect that the motor is actually running.
The first possible fault could be if the motor is trying to turn but the motor is physically jammed. This is likely to be rare. It’s easily tested by opening the door on the washing machine and spinning the drum by hand. If it moves normally and freely it’s clearly not jammed and this is not the fault. If it is jammed or very stiff then making sure the machine is disconnected from the mains supply you can just take off the drive belt. You can then see if it’s the motor or the drum that is jammed. If the motor is jammed it’s likely to need replacing but it’s rare for one to jam.
Drum shaft jammed
This would cause the exact same problem in that the motor is trying to turn but because the drum was jammed it couldn’t. Again, easily tested by turning the drum by hand – if it’s free then it isn’t the fault. If it’s jammed or very stiff, removing the belt will let you determine whether it’s the motor or the drum that’s jammed.
The way a washing machine detects the speed of the motor is via the tacho coil, which is the last potential fault listed. The tacho coil is on the motor under the motor plug cover. It’s at the end opposite to the drive belt with 2 thin wires running from it. It’s a small coil that surrounds the shaft of the main armature where a small round magnet is attached. As the armature turns, the magnet on the end of the shaft turns inside the coil. It’s then easy for the pcb to count each revolution of the small magnet and work out how many revolutions per minute it is turning.
Tacho magnet off or broken
If the small magnet mentioned in the last paragraph has broken, or come loose and dropped off, then the tacho coil won’t be able to pick up any signal from it and won’t detect that the motor is turning. This can also cause the error 7. It’s a relatively common cause in fact. The pcb knows it’s sending power to the motor and that it hasn’t detected any other fault on the motor – but it can’t detect that it’s running.