We do not recommend a DIY washer repair very often.
Most issues need to be diagnosed with live voltage testing / require a multimeter for you to properly troubleshoot. This part of the process should definitely be left in the hands of a professional. By then, if you just need a minor repair, once you have your service call fee waived it won't cost much at all to get the washer working again.
However, it's understandable that some appliance owners will take the DIY route before calling in ann appliance repair professional. It's also true that there are a few issues with washing machines that can be tackled by an 'average Joe', with the right tools.
A defective lid switch is something that many people can replace on their own. This problem is also easy to discover without extensive diagnosing as well. In fact, the main indication of a faulty lid switch is pretty noticeable - your machine will fill up but then do nothing at all. However, a multimeter checking for continuity is the only guaranteed way to diagnose a lid switch problem.
As you know, washers typically fill up even with their lid open (at least, top loaders do). It's when you close the lid that the switch notifies the machine that it can start running the load. If the switch is faulty, it will need to be replaced. This problem often surfaces after letting the lid fall shut, which dramatically speeds up the wear and tear on the lid switch.
To replace, you will need a nut driver, universal screwdriver, pliers, sockets and ratchets. Your owner's manual should provide a complete illustration of how to access and remove the lid switch.
Is your washing machine producing a foul odor? If it seems out of the norm, like a mildew scent, turn to a cleaning solution that either contains baking soda, vinegar or bleach. By far, the most potent bad smell killer would be bleach: Make sure you don't mix it with anything as that can potentially be fatal. Do not rely on the cleaning cycle your washer has because it won't do a deep enough wash to get rid of the odor-causing residue. You can also buy specialty washer cleaners, some which can be included during your normal washes.