NEC PG Series

      >> Introduction
      >> Layout and Setup Tips
      >> Mechanical Setup Procedure 
      >> PG Models and Production Run Dates
      >> PC Control Cable Pinout & Software
      >> Manuals / Downloads

RASTER CENTERING

Make sure the lenses are off the projector for these steps. Now turn the contrast to 0 and the brightness to 100. You should see a clearly visible raster with the actual image within that area. NOTE: If you CANNOT see the raster at this setting, you will have to go into the KELVIN menu first. Turn up the “B” for background slider up until the raster for each color becomes CLEARLY visible. Store this value. Now continue.

NEVER, NEVER, NEVER turn the G2 pots on an NEC unless you absolutely KNOW how to adjust this projector. The same applies for all the other pots on any board unless you are specifically told to do so, and how. If you do... you will need to hire someone like Curt, Doug, or myself to undo the Damage. I need the work.  Thank you. :)

We will concentrate on the green tube first, as this is the “Reference” for everything else. With the electronic position menu set to “0” and stored, the raster should be in the exact center of the green tube. I'd bet it's not, though. All right, first off the raster should not be too wide. It should not be closer than half an inch to the left and right tube edges. To move the raster, you need to turn the 2 tabs of the centering magnets until the raster is centered in the tube face. Use only ONE hand in the projector at any time, and do NOT lean on the frame with the other hand to steady yourself. This is for your safety, in case you get zapped. You NEVER want to create a path through your heart with both hands.

The adjustments are delicate and require finger feel so don't use anything other than your fingers to push the magnets around with.

You may want to use the KEYSTONE menu to make the raster into a rectangle for easier measuring. Work at it to get the raster nicely centered, use a ruler if possible. You can use the GREEN AMPLITUDE setting to increase the raster until it is within a half inch (12mm) of the tube edges, no more than a quarter inch (6mm)! Yes, everyone wants to maximize the raster to use as much of the tube as possible, but the NEC is not designed for this. If you use too much, the electronics run hot, and will be unstable and even fail. You are warned.

Once the raster is centered in the green tube, move on to the red and blue tube and repeat the procedure. You should be met with 3 nicely centered rasters once done. Sounds easy? Not so fast.

IMAGE CENTERING

Ok, you can see that the raster itself is the scanning matrix that the actual IMAGE is contained in. Note that the IMAGE is actually SMALLER than the raster. This is normal, and we will deal with this next. Now use the POSITION menu to shift the image left and right until you center the IMAGE inside the RASTER. The image may get brighter and/or darker while doing this. This is normal. Once the image is centered, store the setting. Now go to the BLANKING menu and adjust the left and right blanking until the blanked area almost touches the IMAGE. You will notice that the image probably gets brighter again, this is normal.

You should see a tiny gap between the image and the blanked out raster visible as a lighter area. You don't want to blank out any of the actual image, just almost touch it. Run the blanking back and forth to see the effect. Don't worry about the top and bottom at this point. NOTE: If you need to resize your video image later on to fit your screen size don't forget to first back out the blanking so you see the entire video image.

TEST PATTERN CENTERING

Now you should have a centered raster, and a centered image within that raster. The next step is to properly phase the internal test signals with that image. To do this, put up the PHASE menu. Adjust the CURSOR PHASE until the VERTICAL bar of the crosshair is dead center in the raster. Store that setting. On some projectors when you enter the PHASE menu you will see a grid test pattern instead of the crosshair pattern. In this instance you will move the “C” slider adjustment until the center of the grid is moved to the center of the video and raster image. At this point you should have a properly centered raster, image, and crosshair. If anything is off, go back and fine tune as needed.

It is now time to put all the lenses back on. You did dust them off first, right? You can also readjust the brightness, contrast and the B Kelvin back to normal levels so that you can see the video image better for the following steps.