Static on Pioneer SX780

[cardoTheCat]

Well, I don't know exactly how to describe it. It's not the usual "scatchy" pot problem. With the input shorted (I'm using the tape and aux to route the TV through the receiver) it is dead quite. If I plug plug in the TV and mute it, then crank the treble all the way up, on one channel, there is static like between stations static, not hissing. And, as I turn up the volume it get louder and eventually it affects the other channel.

I've tried the tape inputs and the aux channel. Somewhat surprising is that the aux channel is affected, it is affect much less. For instance, with the tape input, the static is loud and interfering with the normal audio at 1/4 volume or so. The aux channel is very quiet at 1/4 volume and doesn't degrade until about 1/3 volume.

The unit has never been refurbished. I realize that's probably contributing and may be the a good thing to just go ahead and do anyway instead of trying to isolate the exact issue. Cart then horse I suppose.

[bob91343]

It seems at first thought that the noise is coming from the source, the television receiver.  It's gone when you disconnect that.

If the noise is generated in the receiver, my first suspect might be those cute 2SC945 transistors, or possibly a bad tiny electrolytic capacitor.  Don't 'recap' unless you have a real reason.  It's a lot of work and fraught with possibilities of error.  At the maximum, replace the power supply filter capacitors but even then I wouldn't unless they show signs of age.