TROUBLESHOOTING SHARPNESS/FOCUS ISSUES

Many people complain about sharpness issues. This page will hopefully explain the most common problems and allow you to determine if your complaint is founded :)

Projector related sharpness issues

CRT vs DLP/LCD
A Cathode Ray tube has no grid like pixel structure. Light is emitted when an electron beam hits phosphor particles on the tube surface. Neither the beam, not the particles are square or rectangular shaped so the image will appear slightly softer than DLP. Like your good old CRT monitor, desktop images will appear slightly less sharp on a tube than on a tft screen.

PHYSICAL SETUP & ALIGNMENT OF THE PROJECTOR
Virtually all focus and convergence problems are related to an incorrect physical setup / installation of the projector. If the front of your projector is not 100% parallel to your screen, you will run into serious focus and convergence problems as some parts of the screen will be at a greater distance from the projector than others. In certain cases, the Scheimpflug adjustment of a CRT projector can help, which is basicly a couple of bolts that move your tube in relation to the lense. Unfortunately for us, the Barco 800 has no such thing, so make sure it is properly setup before proceding with focus tweaking.

RESOLUTION
Running a PC desktop on a Barco 800 at 1024x768 or higher will make it look soft. Period. The sweetspot of the projector is probably slightly below that resolution, so the higher the resolution, the softer the image will get. Not that it matters, because we want to use the projector for video, not powerpoint presentations, and in that area, the Barco performs remarkably good even at 1024x768 or far higher. If you want to have razorsharp desktop icons, lower the resolution. Personally, i prefer setting larger icons, or replacing the desktop with some Home Theater automation software. Also, don't forget that Barco CRT's are normally used at much greater viewing distances than most people apply in their home theaters. At a viewing distance of approx 1.5 times your screensize, most video should look just fine.

ELECTROSTATIC VS ELECTROMAGNETIC FOCUSING
The Barco Data 800 uses a focusing technique called Electostatic Focus or ES. Later models such as the 808 use Electro-Magnetic (EM) Focusing, which provides more tweaking ability and faster focus time. ES projectors have are less accurate than EM models and take longer a longer warm up time to reach optimal focus. They are also more prone to convergence drift than EM models. EM is ofcourse more desirable so EM Focusing equiped CRT projectors are more expensive. One of the most popular EM focused Barco projectors is the 808, which in general is about three times as expensive as an 800. Liquid-coupled lense systems provide even better focusing, but models equiped with this technology (1209, Cine9) aren't anywhere near the price range of the 800. I recently found out that Barco also produced a cheaper LC/EM projector called the 1100 series, but according to many, these projectors are very unreliable and tubes tend to stop working for no reason.

Raster Convergence (visible on screen)

CONVERGENCE
Make sure that your Barco 800 has been running while displaying a moving image (to prevent burn) for AT LEAST 45 minutes prior to adjusting or evaluating convergence and focus. If your convergence is not right (yet), the image will look blurry as the three raster dont properly overlap. Not that sudden increase or decrease of room temperature can cause convergence drift as well.

Lense edge focus (visible on screen)

OPTICAL FOCUS
If your projector is mounted WAY out of the distance range that was recommended by the LENS software, you may run into optical focusing problems. Especially around the lense edges it is much harder to get focus right. Follow the installation guidelines in the Barco menu when doing the physical setup and carefully adjust lens focus prior to fiddling with other stuff. The Center and edge optical focus of the lenses can be adjusted by rotating the big bolts on the sides of the lenses counter clockwise and slowly adjusting the front and rear lense rings. Edge and center focus tend to interact a little, so it may take some time before you find the optimal setting. Very slightly out-of-focus screen corners are not uncommon however.

CONTRAST SET TOO HIGH
Setting projector contrast too high (usually > 55) will cause picture blooming resulting in a loss of detail.

Reinier Bauer writes: Blooming depends on the number of hours on the tubes. Older tubes will bloom faster. (Almost) new tubes won't even bloom at contrast set to 80 or higher. This difference is caused by the aging of the cathode material, which makes electron emission more difficult. The cathode in the tube has a pointed shape and due to aging, emission will not only occur from this point but from a larger surface, resulting in a larger spotsize or bloom. It doesn't really matter if the tubes has many hours on it and no wear or many hours and much wear. The cathode will always deteriorate over time.

Beam Focus (visible on tube)

TUBE ELECTRONIC FOCUS
In some cases, the focus of the electron beam on the tube surface can be off. Electronic focus is set by turning the focus controls on the side of the projector. You need to be VERY careful when doing so, as these controls are very close to the power supply of the projector. Touching the wrong things can be LETHAL. The focus pots are below (ceiling mount) or above (table mount) the G2 controls. Select your video source, put on some sunglasses and look into the tube while carefully adjusting the focus pots for each tube while projecting the Genlocked pattern that can be found in the "Random Access" menu of the Barco. Note that in many cases, the blue tube will be set slightly out of focus (defocused) on purpose, to create more evenly blues and prevent yellow areas in bright images. Also note that after tweaking electronic focus, you will need to redo all your convergence and color adjustments as they are affected by this setting.

RGB Output stage failure (visible on tube)

RGB OUTPUT AMPLIFIER PROBLEMS
When the components in the RGB amplifier boards behind the neck of the tubes fail, usually the Q6 FET (2SK511) is the first to go. One of the early symptoms of this failure is a horizontal streaking to the right in the video image. This reduces detail, makes the image look washed out and can make certain colors in the projected image appear to be severely out of focus. Read the DIY section on FET replacements to learn more about this problem.

Video source related sharpness issues

SOURCE QUALITY
Ugly ass DVD's will look ugly on your TV, but they will be FUGLY on your Barco. Small blemishes, noise and other crap is magnified on the big screen, and particularly the cheaper dvd releases will contain a video transfer that is so bad that no matter how sharp your Barco can project, it will still look like you have grease in your eyes. Look for anamorphic versions of your favorite movies, perferable on DVD-9 discs as they require less compression and show more detail.

AC INTERFERENCE / THE IMPORTANCE OF QUALITY CABLING
Crap cables cause crap video. If you dont use shielded VGA to RGB cable, and place it near powercords, the Barco will pick up a lot of interferance resulting in a loss of sharpness, a jumpy video image and all sorts of other artifacts that cannot be resolved by tweaking the electronics or physics of the projector.

Miscellaneous

Having trouble focusing the blue tube?
Many people report having trouble focusing the blue tube. This is often simply due to the fact that the human eye is not very sensitive to blue color detail. Note that it is even harder to focus blue if the G2 settings of the tube are incorrect. The blueish haze or crunched/lacking detail in the tube image caused by this can make it even harder to focus on detail in the image. However, G2 is not something to mess with, so don't touch it unless you are absolutely certain something is wrong. Read the G2 section on this website for more info about this and the risks involved.

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