So, I have a Tandberg TCD-420A cassette player that I absolutely love! It works great, but the output volume slider pots are showing symptoms. Both, but especially the Left side, cut out sometimes. If you lightly tap, or move the level up or down, you can get it to come back, but then goes scratchy or out again after awhile. Another, possibly related symptom is that sometines the sound goes up and down a like a wave, while the cassette is playing. Gets really flat and muted sounding, then swells back up to bright and clear. Seems to happen more when first starting a cassette. At first I thought the tapes were bad from being old, but it appears to be the player. So, I found the quote in the pic, and want to address these pots. I'm guessing Fader Lube, but do I just spray through the front in the 'track' of the slider, or a different way? Or is something other advised? I'm really scared of doing damage after having a round pot problem after using Deoxit5 on a different component!