And there never will be anything in the user guide - they don't want you messing around inside - very high voltages and radiation lurk inside a microwave - potentially dangerous even when switched off and unplugged - the expectation is that you will hire the services of an expert specialist to do the work.
Remember lord Finchley
Lord Finchley tried to mend the Electric Light
Himself. It struck him dead: And serve him right!
It is the business of the wealthy man
To give employment to the artisian.
Peccavi, February 2013