A blob is appearing on every frame could that be dirt on the sensor? If it is dirt on the sensor, how do I clean it?

The back light is broken then and also this will happen if there is too much pressure between the panel or and the frame and the back light that has the the display to appear on your TVs screen is , making a warping effect to show up.

Most likely your DMD chip has dust or hair on it. You can try blowing it out with compressed air but the best thing is to tear down and clean the dmd chip itself. Very carefully. Here is a video of a similar unit. SO far all the DMD projectors I have worked on have had a very similar set up. Take pictures as you go.
MItsubishi XD206u DLP Projector Lens Assembly Cleaning

It has the error code for condensation cheack the sensor (see photo link below) If it is very dirty it will appear like a small square circuit board about 5mm x 5mm with a black blob in the center and two solder connections at the top. After cleaning you should see a bright copper circuit where the black was prior to cleaning. Gentle wiping with an alcohol moistened cotton bud is all it needs. it looks like this http://www.dvinfo.net/forum/attachments/sony-hvr-a1-hdr-hc-series/12072d1241502823-moisture-condensation-dsc01114.jpg

this is usually caused by dirt inside the light engine.  it needs to be sent in to sony or a rebuild company to be cleaned or replaced.  not user/operator repair....

Dark spots are usually the result of dust or dirt on the lens. If a simple soft bristle brush (1/8" wide paint brush is ideal) can't dislodge the debris, you should purchase a lens cleaning kit available from camera stores. They run about $10. These are great to removing these and other contaminants such as finger prints, smudges, etc. High end lenses have special optical coatings and the special cleaning fluid included won't leave a residue - or damage the coatings.

If the spots are bright or colored, (or dark after cleaning above) the electronic sensor inside the camera has a "hot" or "stuck" pixel. This problem is usually not worth fixing due to cost.

I hope this helps - and good luck!

You might have to have your sensor cleaned. When the camera body is exposed to excessive amount of dust they can get in the mirror housing. When the shutter opens and the mirror flips out the way when a photo is taken, it aggitates the dust then it falls on the sensor. It will need to professionally cleaned by a repair technician.

To test it is dust, take a few photos of a white wall at aperture f22 with the flash on and if they are all consistant that is problem. They will look like soft black blobs.

It's not the lamp. It maybe dirt or dust or even a bug. The picture that is projected starts out 1/2 inch by 1 inch in size. Somewhere along the path to the screen a piece of dust gets in and after it's projected it looks like a blob on the screen. The closer it is to the DLP chip itself the bigger it looks. If this is the case you should have a professional service it. The Light engine needs to be removed and cleaned.
If you lightly push on the screen does the blob move slightly ? If it does it's not on the screen it's in the optics or the mirror.
You may also have a bug or smug on the main mirror that causes the same thing. This will appear about 2 times the normal size of the object. If your up to removing the screen Take a look closely at the mirror on the back of the set. You can clean this with windex it's glass. If you do take the screen off hold it up to the light. Sometimes spiders make webs and leave marks.
Good Luck

the fuser has burbt toner on it most likely you will need to replace it.

Sounds like you have your "blob" on the actual CCD sensor in the camera. There are special "cleaning kits" to remove dust etc. from the sensors without damaging them. I would not suggest trying a "home-brewed" system of cotton swabs, isoporpyl alcohol, and a can of compressed air, unless you were very well versed in this operation. A scratch on the sensor will ruin the camera. Have a qualified shop do it, or buy the sensor cleaner kit, if you want to be safe.

try to clean and calibrate the cartridges with printer softwar