On Tue, 04 Jan 2011 08:39:31 -0500, Tim Schwartz
wrote:

Hello and Happy New Year all,

I've got a Luxman R117 receiver here that breaks into a wild
oscillation when the amp is pushed. I believe that it occurs when the
amp switches from the low B+ rails to the high B+ rails. Turning up the
treble control seems to make it worse, but that might be a red herring.

I've changed all of the electrolytic capacitors in the tone circuit,
I've tested and substituted the 4 main filter caps. I've check the
suppression network on the output.I this this is some sort of decoupling
problem, but I've sent way too much time on this receiver. A friend who
worked on these when they were under warranty has looked it over as
well, and we're both stumped.

Anyone in the group seen anything like this on a Luxman R117?

Many thanks,
Tim Schwartz
Bristol Electronics


Is there a possibility that someone has changed the outputs or drivers
with faster transistors than the OEMs? Chuck