Greg wrote:

Our faithful, 20 year-old Yamaha R-50 recently failed to power on.
After checking things like the power cord and outlet, I carefully
removed the cover and found a blown slow-blow fuse close to the the
power transformer. I replaced this 250v 4a fuse and now the receiver
will power up (lights on the console are lit). However, I am still
getting no output to either the speakers or headphones, from either the
radio or aux (CD) sources. Is there anything else that a careful novice
like me can try or check, or is our receiver a lost cause?

Many thanks for any suggestions,
Greg

you most likely have bad Caps in the power supply..
a lot of receivers have power supplies that
sample the voltage at the main caps while they
are being charged via a resistor to allow for slow
start up to avoid inrush currents.
when the desired charge is reached, a relay will
bridge this trickle charging system to allow full power
and also start the receiver.
since your fuse was blown, it's possible (theory only) that
one of your caps or even a bridge rectifier has shorted and
is not allowing for the voltage to reach its peak, which btw
must be the reason why you didn't blow out the new fuse you put in ?
if this is the case, you should have a high wattage resistor getting
vary hot!, or maybe by this time has opened or unsoldered it self from
the board ?



--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5