"Greg" wrote in message
ups.com...
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

Be careful with Google - since Yamaha also made an R-50 helicopter :-)

I never view equipment as a "lost cause" unless extensive damage has
occurred (e.g. lightning) to a large number of components.

The Yamaha R-50 service manual is available.
http://www.vintageaudiomanuals.com/-XYZ-.htm

My troubleshooting regime starts with the power system. Is it functioning
properly (proper voltages, etc.). Since you replaced the fuse and you are
getting power to some devices (lights) - this would lead to in the following
direction.

BTW all of this work if performed with the receiver unplugged from AC mains
!!

1. Check rectifier (bridge or full wave design). Verify voltages correct
(service manual helpful here).

2. Go to Power amplifier stage. I am not familiar with this model, but for
this era - 2N3055 NPN transistors were not uncommon. Take out of circuit
and test each -- as well as any ballast resistors.

That's a start.

gb