Blinking Channel LEDs with side of noise

[ManRay]

Hi,
I have a quirky Crate TV-120 with a clean channel issue. When I play it on the clean channel the red dirty channel indicator LED will blink inconsistently while the green clean channel indicator stays steady on. The red channel indicator seems to flash brighter when I strum heavier. This blinking accompanies abundant amounts of really bad noise that resembles scratchy pots.

This leads me to my next symptom, an inconsistently scratchy volume pot on my clean channel which does not respond evenly along the length of its travel. It may be completely unrelated, but I thought it worth mentioning.

I noticed that pushing down on the tubes will have an effect on the noise, so I replaced the tubes before I noticed the schizo LED and got no improvement.

I've attached a .pdf of the schematic to help.

Thanks again,
Mr.

[Jazz P Bass]

Crate LED

I had one of these amps on the bench for a tune up.
Nothing wrong, just clean, resolder, check it out.
When finished with the servicing, I noticed the Red LED trying to come on when I had the clean channel on.
I fussed with the diode, the 1K resistor.
I ended up with a 2.2K resistor in there, but it still tried to turn on when strumming hard.
I think it is a crappy circuit design.
It is what it is.

[ManRay]

Bad noise

What I am really concerned with is the noise that I am getting. I thought maybe the LED was a related issue, but if not then I can let that go easy enough.

Did you notice any scratching or unwanted sound that accompanied your LED blinking? It is like the true sound of the amp is being restrained and it only breaks through intermittently. Like maybe a faulty switch between channels is causing both channels to try and run simultaneously? I have a multi-meter and can run simple tests if you can point me in the right direction.

Thanks,
Mr.

[Amp Kat]

Without a schematic or model # it's hard to say but it sounds like an optoisolator that is passing DC. They are very sensative to temperature and fail quite often giving those symtoms.

[ManRay]

Optocoupler?

The schematic should be in PDF form in the first post and the model is a Turbo Valve 120.

How can I test the component to determine if it needs to be replaced?

Thanks,
Mr.