Sometimes when my 606 is off there suddenly are black lines on the display. When I put it on they will slowly start to fade out but leave little artifacts and bleach out some parts of the screen a bit. Even when I mess with the contrast it doesnt have much effect. Sometimes they just dissappear after some second but sometimes they will remain a while.

Anybody has this problem or know if it's really bad or how it can be fixed?

same things happen to me too!i don't think it's something bad....!

the first 606 i bought as a scratch and dent from musicians friend for about a hundred less than the "new" price. after messing with it for a few days, the lines were coming up on the display at random times when I had it on or off. I called and exchanged it for a new one with no extra charges. I have had that 606 for about 5 years and the screen has started to do the same thing. Sometimes it takes powering off and on a few time to get it to clear.

Yeah, I would say it has to do with age. If you spend 8 to 10 hrs a day with the screen on, then lines will appear in time. Nothing worry about, unless the entire screen goes black.

i just remembered that i had this problem when i used an other power supply...although it had the same specifications the screen used to be filled with black lines...so if you can find another power supply check it...
(be sure to have the same polarity!)