What way do you guys use to make sure the PJ is aligned to the screen?

Trying to make sure my 10PG is centered on the screen and the face of the green tube is parallel to it. I tried a string line down the center of the PJ and a laser light off the flats sides of the chassis. Should I be using this method or since I maxing out the image on the tube should I use a projected full screen pattern? I can not get the image perfect in the center (it's off by maybe a sixteenth) of the tube so it's getting a little confusing.

Thanks, Deron.

Use a external test pattern from the source (Avia). You need to have linearity close to perfect esp on the 10PG. Measure the screen and put tape at the center of each side top and bottom. Correct linearity using the cross hatch then go to the cross hair and line up with the tape. Go over this a couple of times.

If the rasters are centered and the image centered in the raster it should be pretty close.

If your running more then one freq the position will be a bit different because of timings.
This isn't so critical if the 10PG has the Plus upgrade where you have control over the edges so optically it needs to be pretty exact for best overall focus and corners.

Before starting have H-V position at mid point. Make sure mechanical astig is perfect at center. Doug

I used strings or just measuring tape from front corners to screen corners for centering the front of the pj and rear corners for rear centering. It is easy and works.

I also used Caspian's method as a means to ensure that the PJ is correctly mounted/aligned mechanically. Just centering the controls and putting up a pattern isn't nearly accurate enough in my book. I was shooting for 1/16th inch perfection in mechanical setup and eventually settled on 3/32" being good enough.

So Doug, I want to get the image from my Avia disc centered in the raster with the raster centered on the face of the green tube. I can then project a cross hatch out of the green tube onto the center of the screen. This will get me started, but then are you saying that I need to project a crosshatch pattern from each tube and align the PJ so that I get correct linearity?

I agree that Caspian's method will get the PJ's chassis correct (make sure the string you use will not stretch), but could using a image that is centered on the face of the green tube get you closer? If you had a perfect crosshatch pattern with a centerline, you could line up the centerline and then move the PJ till the crosshatch at the edges were correct. Problem is, who knows if the linearity is correct on the crosshatch pattern. What might work real good is to use a cross pattern out of the green tube onto the center of the screen and then measure the corners of the chassis to the screen sides.

I ordered Graham's set up DVD, not here yet, but that will be interesting to see how he does his PJ's.

I think I will just shoot for close right now, as I know I will go through the set up a few times before I will be totally happy.

Deron.

Elaborating on Caspians method... I scanned this from a docs package from a F.A.T.S. projector I picked up.
There is a little subtlety with the marks on the strings, but it is really clever.
Specifically, when the strings are taut, and the marks aligned, then the PJ is square and centered... If out of square, the marks will be unaligned... if off-center, the marks will be unaligned.

Your projector can be exactly squared up but if the image isn't in the sweet-spot of the lens it wont be squared up to the screen for uniform focus. This is important on the 10PG.

On linearity side to side correct until the width of the cross hatch test pattern box is the same for both sides then correct top to bottom so the height is the same top and bottom. Check these on the out most box first.
The cross hatch pattern box will not be exactly square so don't confuse this.

After getting that dialed in use the cross HAIR test pattern to center to the screen then go back and check linearity. When your close you should be able to measure from the center cross hair to the outside edges and it will be the same. In short the image is in proportion over the entire area and will hit the lens 'roll off' the same.

We all have our different ways to do things but I find this works the best for me when you have a projector that doesn't have alot of mechanical ability or separate edge focus / astig. Doug

Foley

I took a look at that and it looks real easy. I would just use two tape measures instead, as it would be easier then making up a set of alignment cables with the proper marks. Just hook the dumb end of the tapes to corners of the PJ and pull the tapes up to the screen and attach them there or have someone hold them there. Now check the measurement at where they cross and it should be the same for both tape measures, if the PJ is correct to the screen.

I guess these are Isosceles triangles, two angles are the same and two sides are the same.

Your tape measures will create the two sides that are supposed be the same on each triangle. The screen and the PJ will make up the third side. When the tape measurements crossing points are correct you will have two sides that are the same and two angles that are the same on each triangle. Sense the triangles are fixed to the tape measures that make up the two sides, this will cause the third side of each triangle to be parallel and also perpendicular to a centerline drawn though the PJ and screen. Real easy and almost impossible to screw it up.

Doug, I guessing the patterns off the Avia disc should be perfect, that's my only concern, that somehow they are off, either by the PJ having some sort of problem or the disc itself is not perfect.

I'm going to use both methods, measuring the PJ itself with a tape and then projecting a pattern and measure the results on the screen.