I have a turbo v ion source that shows a glowing blue/purple light at the tip of the Heated Nebulizer corona discharge needle, even when it is not in use and turned out of ion path as it should be when using TIS probe. It only happens in negative mode. It is not arcing to the cutain plate, just a slight noticeable glow at the tip of the corona needle when observed through the front window. My FSE has rebuilt the HN probe and components and also installed a new TIS probe. Still glows when in negative mode. Note also having poor sensitivity in negative mode as well and jagged peak shapes during infusion. Any ideas? Are the symptoms related?

Thanks, Jon