Re: Yamaha R-50 receiver failed

Jamie wrote:
<snip>

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 ?

Half-baked gobbledygook.

1. A shorted rectifier or main filter cap would blow the fuse every time,
not just the first time.
2. The receiver in question has a DC and current detect circuit, not a
simple R/C delay for the relay.

There is only a small chance that the OP's receiver can be repaired at all,
since the main output IC is no longer available, and is VERY likely the
fault. The only definitive way to know for certain is to troubleshoot with a
service manual and a knowledgeable technique. Since the OP has neither of
these, money spent getting a repair estimate is a low-percentage proposition
(free estimates are a thing of the past). Add to this the fact that it
wasn't one of Yamaha's best to start with, and there is near-unanimity on
the group, including the OP, that the receiver should just be replaced
instead. New and high-quality vintage gear abound.

Mark Z.


.

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