This issue is occurring in a school classroom. We have a variety of projectors to choose from so I have tested other models to help determine the cause of my issue. All different types of projectors that I have used to test as replacements have the exact same problem. The only projector that produces a clear image is the same model as the original projector.

Any replacement projector I have used all have the same problem, waves of dark horizontal lines that move from top to bottom in a relatively consistent pattern. The intended image does project clearly but the dark waves are very distracting.

Original setup worked great since install. Teacher says the projector just turned off one day. My diagnosis of the projector is a faulty internal power supply.

I have done a thorough diagnosis of the setup by replacing individual pieces of the parts used for both sides of the setup (pc side and projector side), including all power supplies for the cat5 extender, vga cables, and cat5 cables. All replacement parts used were confirmed to work properly because we have the exact same setup in several adjacent classrooms. I moved each part one by one to make sure I knew which part of the setup was causing the issue. I wanted to think it might be interference but if I use a projector from another classroom that is the same model as the original, there are no waves. That alone tells me that all original components are not faulty.

I am trying to find the difference between two of these projectors in hopes of narrowing down the cause. Links to the mfg websites for the components used are below.

Any help is appreciated.

Thanks.

Original projector: HP vp6310 ---- http://h20000.www2.hp.com/bizsupport/Tec...ectID=c00277938

Testing projector: Epson PowerLite S4 ---- http://www.epson.com/cgi-bin/Store/consu...es&oid=63058359

The projector is connected to a PC by way of cat5 extender box Startech VGA Video Extender (model: st121utp) ---- http://www.startech.com/item/ST121UTP-Co...P-Extender.aspx