My friend has a projector which he has asked me to fix because it has a white line going across the screen. i have thought this to be the dlp chip but i just need a second opinion

You need to clean the lenses in front of the light bulb and clean out the inside of the light box too

Your DLP chip is damage or getting to been damage.
** To make it sure you can do it your self by getting some basic tools such as proper screw drive, and open your projector for parts.
And you can physically observe the Chip.
Please check by side angle on the chip surface. **

This is a dlp projector and has a bad DMD chip. Most models are very similar. Here is a video of a similar repair.

The DLP Chip is failing .The DLP or Digital Light Projection Chip contains up to 8 million tiny microscopic mirrors that tilt to project a digital image onto the screen. These mirrors are failing causing light and dark spots to appear.Unfortunately fixing this projector is probably going to cost more than buying a new one. Hope this helps.

means the DMD chip is broken,you need a new DMD chip.I supply the DMD chip and the price is USD120

Your dlp chip is going bad and cannot be fixed economically. Several of the mirrors on the chip are hanging up and they won't come back. It will just get worse. My Sharp XR32X is doing the same thing. New projector time.

Clean and verify the color wheel and its sensors. They can get dirty and wheel no longer syncs. The next thing is if the air cooling of the DLP chick got clogged that MAY have damaged the chip. It moght be permanent but check that the air passages for the heatsink of the chip are open.

Sounds like the DMD chip is getting bad pixel failure. Most likely the chip will have to be replaced.
If the white spots are well defined and rectangular in shape when you get up close to the screen, then this would confirm the problem.

Just tell your friends that it's snowing in Kenya and the snow flakes are getting on the screen and ask the children to try and brush them off. Make the most of it until you can get it fixed, or get another broken one that has a good dmd chip and swap parts.

try to check dlp chip inside the projector maybe dlp chip got problem or very dirty or check whether color wheel got fungus and try to clean it.

that is due to lcd filter units , try to align, precision work