No life whatsoever in your machine? Not a sound, not a light?
Sometimes it is the most obvious thing that is at fault. This picture
shows that internally some of the Betamax machines contain serviceable
fuses. Before trying to test this fuse though it is well worth
checking the fuse in the plug.
Before you do attempt to change the fuse, make sure the power is disconnected and be aware of any capacitors which may have a high charge on them. It is best to leave the machine a few minutes after disconnecting it before attempting any work.
If the fuse has blown, then you must consider why has it blown? There may be a more serious fault in the machine.
N.B. Videos recorders do not require a 13 amp fuse. A 3 amp fuse is easily enough, any more than this could be dangerous. Also make sure that you replace the internal fuse with one of the same rating.
The next most probable reason for a dead unit is a more serious problem with the power supply.
See also the section nothing happens in the repair guide.