The sensor is dirty. The next time you change the bag, leave it off and the cover as well. Plug the sweeper in and turn it on for a few seconds. The lights should blink then run steady. This is the best way to blow out dust. It should be done outside.
Many people are not seeing the washable filter at the top of the vacuum cleaner. You can't see it until you open it. This will cause the vacuum to overheat and shut down when not cleaned.
https://www.youtube.com/watch?v=kzhlvB2LjXgControl Lock
Thank you for your question and I understand your concern. The "LOC" indicates the (Control Lock). This means the control panel has been locked and it will have to be unlocked before you can use the dryer. To unlock the control panel; press and release the Option and Select buttons at the same time.
The letters (LOC) indicates Controls are Locked. To avoid having someone accidentally start or stop the washer, press OPTIONS and SELECT at the same time until the Control (Control Lock) indicator is lighted. the controls, press OPTIONS and SELECT at the same time until the Control (Control Lock) indicator goes off.
Turn it off at the mains. Leave it an hour and start again.
Here is your manual in case you need it
https://www.manua.ls/hoover/hn-6135/manual
and even a 1 hour video :>)
Crackling certainly doesn't sound good. How many days past warranty.
Contact them, " 2 weeks ago my washing machine stopped working, I was going on a business trip, and couldn't do anything about it. I checked the fuse and it had blown. I replaced the fuse and it still doesn't work. When the machine failed it was in warranty, please come and fix".
If not, the most likely issue for 'crackling' would be the control board or the motor, leaning slightly to the control board as it has no power visible to it. A failed motor would have power to the board, but nothing happening.
There is a break in the wire probably around the handle or plug. Turn the vacuum cleaner on and shake the cord. If the vacuum cleaner shuts on and off, replace the cord.
I am not sure about your particular model. But I had a small cheapy Hoover Upright that would not turn on. I pulled it apart (lots of screws) and found the inline fuse blew. I was able to fine a inline car fuse and install it and it worked fine.