It's usually a small capacitor. You need an ESR meter to check them. You can
replace the entire power supply, if it's still available for about $200.00 so
you may *not* want to pursue that avenue.

We had a power outage here a few nights ago and when the power was
restored my Sony SLV-R5UC would not turn on, the clock was dead
ect.This problem has occured at least 7 or 8 times through the years
since I bought the VCR in the arly 90's. Has anyone else experienced
this problem?

I suspect the problem is the switching power supply. Does anyone have
an idea on what I could check in the power supply to see if it is
still functioning. The supply has had a lot of work done on it and I
would consider buying a replacement unit.

Does anyone know where I could purchase a new power supply and what it
might cost? Thanks in advance.