Skratchie,
Are you OCD with details?
Are you mechanically inclined?
Can you read a manual?
If you answered yes to the last two and anything better than
what's ODC to the first, yes you can do it yourself.
Before you tackle it I will tell you the 500 has some quirks that are a bit of a pain to deal with, but that is what makes it one of the best machines Singer ever made.
The side to side moving parts that make it ZZ can and do become gummed up from old oil when the machine is not used. You need to clean them thoroughly. This is at the needle bar end and at the cam stack end. There is a plunger at both ends.
The stitch pattern adjusting knobs can become jammed up internally if dirty and old oil accumulates on them. There is where the OCD comes in, there is a lot of levers and linkages to clean.
With this machine cleanliness is next to Godliness. Clean it good, keep it oiled and greased and you'll love it.
I should know, I have two of them.
..... My wife only has a 401a ........
Ask any questions you need to, but if you didn't get an owners manual, go to the Singer site and download one. They are free and absolutely necessary in my opinion.
Main manual page: {
http://www.singerco.com/support/instruction-manuals }
There is also several threads here about what lube (oil and grease) to use on the 401s, finding and reading those might be educational and entertaining as well, as the 500 is the same internally as the 401s.
Joe