Good evening, folks. I wonder if there's anyone who can help. I'm looking at my Dad's old NAD receiver for him. The story is: it stopped working for him and he left it for a few weeks. I took a look inside to check the fuses, found they were ok, and then realised on testing the unit was working perfectly. It worked for a little while, then stopped again. Fast forward a few weeks, I bring the unit back to my place for a closer look. Same thing again: on initial testing all worked perfectly, all inputs, all outputs. The next day I tried it again, this time nothing, or more accurately:
Power up: relay clicks, LEDs/display operate as normal, some initial hum audible over headphones which reduces over a short time. No signal audible over headphones or either speaker channel.
Taking a line out of the preamp out confirms that all is well there, and that the problem lies in the power amp section.
Usually I would suspect transistors but not for an intermittent issue!
Do you knowledgeable folk have any thoughts about what I should look at next? I'm armed with a multimeter, a soldering iron, some common sense, some experience with electronic repair but not a lot of electronic theory. I'm willing to learn!
Many thanks for your time. Happy Christmas!
Power up: relay clicks, LEDs/display operate as normal, some initial hum audible over headphones which reduces over a short time. No signal audible over headphones or either speaker channel.
Taking a line out of the preamp out confirms that all is well there, and that the problem lies in the power amp section.
Usually I would suspect transistors but not for an intermittent issue!
Do you knowledgeable folk have any thoughts about what I should look at next? I'm armed with a multimeter, a soldering iron, some common sense, some experience with electronic repair but not a lot of electronic theory. I'm willing to learn!
Many thanks for your time. Happy Christmas!