SuperMac Displays Q&A


Q: When I connect my display to my SuperMac video card, instead of getting a usable picture, I get a distorted, scrambled image. I know the monitor is compatible with this card -- what else must I do?

A: SuperMac cards must be configured for the specific display to which they are connected. If you move the card to a different slot in your Mac, connect a different monitor to it, or zap your Mac's PRAM, you will need to reconfigure the card to output the proper signals and timings required by your display. To reconfigure your SuperMac card, hold down your keyboard's Option key at startup. Continue to hold down the Option key until the "Round Robin" configuration cycle begins. When you see an image of a keyboard that is clear, centered, and at the resolution you want to use, press the Space bar. The computer will then restart, and the card and display should now be properly configured.

Q: The screen is "vibrating ," "jittering" or "shimmering ." What causes this?

A: The usual cause of this sort of problem is outside electro-magnetic interference. This can be caused by several different things (i.e. power lines, power transformers, electric fans, copiers, scanners, printers, other monitors, large metallic objects, metal shelves, metal desks, etc.). The best way to test this sort of issue is as follows:

1) Your display may use connectors attached with three or five colored wires on one end of the video cable. These connectors are called BNCs. If all five are attached but you are NOT driving the display from built-in video, try unplugging the white and black cables, leaving only the Red, Green, and Blue cables connected. (If you are using a Power Macintosh with the display plugged into the built-in video, all five connectors will need to be plugged in.) On most Quadras and video cards, only three are needed. The presence of the extra BNCs in an environment where they are not needed (on a Quadra or a card) can cause jitter. If removing the connectors causes the screen to lose its image, then your monitor needs them connected.

2) Turn off any electrical devices near the monitor, and see if the problem lessens in severity, or disappears. If the display is plugged into a power strip, try plugging it directly into a wall outlet.

3) Try moving the monitor to another location. This the best test of all because it eliminates many unforeseen variables. If the intensity of the problem changes as you move it to different areas, that would point to an outside influence as the cause of the jitter.

4) Try changing the resolution of the display. If the problem lessens or increases in severity, you may have a bad video card.

5) Test it with another video card or built-in video. If the problem goes away with a different card (tested in the same physical environment), then that would point to it being a card issue.

If all of these suggestions fail to resolve the problem, call Radius Technical Support at 650-404-6400 for further troubleshooting assistance.

Q: Why are there two faint gray lines about one-third from the top and one-third from the bottom of the screen on my SuperMac display?

A: This is a characteristic of all aperture grill or tension grill display tubes. These lines are shadows from the two stabilization wires mounted inside the tube. These wires serve to keep the tube's aperture grill in perfect alignment, producing the sharpest picture possible. You would even be able to see these lines on a Sony television if the picture were sharp enough.

Q: I have a SuperMac display that I would like to connect to the built-in video port of my Power Macintosh. I know I have to use the correct cable adapter to achieve a particular resolution, but is there anything else I should know about this combination?

A: Due to changes to the Mac's built-in video which first appeared in the Quadra 660AV and 840AV and now exist in the Power Macs, many SuperMac displays require a new cable in order to work properly. Any SuperMac display that has five BNC connectors for red, green, blue, horizontal, and vertical signals (excluding the STD9455 monitor, also known as the GDM1952, which has 5 BNC connectors but uses an unsupported timing, but including the SuperMatch 17•T, which has a hard-wired cable) will be compatible with Apple's new built-in video architecture. If you have a monitor with five BNC connectors, but have a cable with only three BNCs, then you may order service part #0009344-0001 by calling our service department at 800-977-7060. Color displays which have three or fewer BNC connections will not be compatible with newer Macs unless a compatible graphics card is used. Similarly, greyscale or monochrome displays must have two BNC connections, not one, to be compatible with the built-in video of newer Macs. Most older SuperMac displays that use a DB-9 connection are not compatible with any Macintosh built-in video.

Q: My display makes a popping sound. Why is this happening, and what can be done about it?

A: In some ways, the Cathode Ray Tube, or CRT, is like a light bulb. It contains internal components that bring the image you view to your screen's surface. High Voltage electrical currents inside the CRT are used to accelerate the electrons towards the CRT face to illuminate the phosphors and produce an image. If a minor electrical imbalance occurs inside the display, the display may discharge its excess voltage to one of the components inside the CRT. We believe the imbalance in electrical potentials to be caused by tiny charge-carrying particles inside the CRT. These particles, if existing in sufficient quantity around the CRT gun or some other internal component, may create enough of an extra negative charge that the high voltage charge in the CRT will flash over to it. This discharge is what causes the audible "pop" one hears. The screen usually blanks out momentarily, and then comes back, sometimes out of focus. The focus usually clears within twenty minutes.

There are two important facts you should know about this issue:

1) The monitor has a special built-in protection circuit which helps it deal with internal surge that accompanies these flashes. There should be no damage to your monitor, your computer, or yourself.

2) Some of the particles believed to cause this issue are destroyed during each pop. As a result, the problem usually disappears within several weeks.

The best recommendation we can make to a user with a popping display is to let the monitor continue to pop for a few weeks. If the problem does not go away or lessen in occurrence, then the customer should contact Radius Technical Support at 650-404-6400 for further assistance.

Q: Whenever I startup my Macintosh or display a dithered gray background, there are rainbow-tinted, curved lines running across the entire screen. What is causing this?

A: Certain types of display tubes will display what is known as a "moiré" pattern whenever a grayish checkerboard pattern of black and white pixels is displayed on the screen. The default Macintosh startup is a prime example. The moiré pattern that is generated is not a problem with your monitor, but is a normal trait of aperture grill displays. You may change your desktop pattern to a solid gray or another color in order to prevent this moiré pattern from appearing. However, some image-editing applications, such as Adobe Photoshop, use this dithered pattern to mask out the desktop background which unavoidably causes the moiré pattern.

Q: I have an older 60Hz SuperMac display. Can I connect this to the built-in video port of my Macintosh?

A: No. Macintosh built-in video only supports a 75 Hz refresh rate. To use an older 60 Hz SuperMac display, you will need to install a graphics card that supports that refresh rate, such as the SuperMac Thunder/24 or almost any late-model Spectrum card.

Q: Why don't I get any picture when I hook up my 20" SuperMatch display to the built-in video of my Quadra 700? I'm using the 1024x768 cable adapter, but it doesn't help.

A: The Quadra 700 & 900 lack the proper oscillator and cannot support the normal 19" or 20" mode of 1024x768 resolution. The only solution to use this resolution with these Macs is to install a graphics card.

Q: Does the SuperMatch 21•T XL SuperRes display use a Sony Trinitron™ tube?

A: No. The 21•T XL uses a Mitsubishi DiamondTron™ tube. Sony's exclusive patent on Trinitron™ technology has expired. Mitsubishi has licensed the Sony Trinitron™ technology and has improved it to offer a 21-inch tube with a crisper image and a longer mean-time-between-failure rating.

Q: What do I need to connect my SuperMatch 20•T XL or 17" Multimode to my Windows™ PC?

A: You need the 5-BNC PC cable for PC platform compatibility. This cable has five BNC connections on one end for the display and an HD-15 connector for the computer's video subsystem. The part number is STD3535. It can be ordered by dialing 800-977-7060.

Q: I'm having trouble getting my SuperMatch 17•T to work properly with my Spectrum/24 Series III graphics card. What's wrong?

A: For this specific combination, you need to use the 0008602-0001 adapter. It can be ordered by calling our order fulfillment department at 800-977-7060. At the time of publication, this part was in extremely short supply and may not be available for very much longer. No future production runs are anticipated to create more of these adapters.


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