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Aptiva - Degaussing: Explanation and how to degauss IBM monitors

Applicable to: World-Wide

All color Cathode Ray Tube (CRT) monitors are very sensitive to magnetic fields. If any parts of the CRT are magnetized, then the front of screen performance will be degraded. The primary effect of this degradation is loss of color purity, which may manifest itself as color distortions or "shadows" on the display. All IBM monitors contain automatic degaussing circuitry which activates every time the monitor is powered on. This process is designed to eliminate magnetization of the CRT. If the monitor is subsequently moved or rotated (thus altering the magnetic field around the monitor), or brought into close proximity with another strong magnetic field (unshielded speakers can generate such a field), then color purity problems are likely to occur unless the monitor is degaussed again.
Degaussing can always be performed by powering off a monitor, and then powering it back on. Ideally, a monitor should be left powered off for at least 30 minutes to allow the degauss circuits time to reset, and hence, operate effectively when the monitor is powered on. Some IBM monitors feature a manual degauss button that enables the user to operate the degauss circuitry without having to power off the monitor.

The IBM monitors that do include this type of manual degaussing feature are listed below. For all other monitors degaussing can be performed, as noted above, by powering off the display off for at least 30 minutes, and then powering the monitor back on. Note the screen will become distorted, and you may hear a slight buzzing noise while the degaussing takes place.

G52 monitors: These monitors, like all IBM monitors, automatically degauss themselves at power on. In addition, these monitors can be manually degaussed during operation from the on-screen display. Activate the on-screen display by pressing the Select button (this is the button directly to the left of the rotary control). Once the on-screen display appears, use the rotary control to highlight menu option 5, and the press the select button again. The sub-menu will appear, the first option on the menu should already be highlighted, press the select key to activate the degaussing circuitry.

G70 and G70t monitors: These monitors, like all IBM monitors, automatically degauss themselves at power on. In addition, these monitors can be manually degaussed during operation by pressing the right-hand side of pushbutton 11 (this is the right-most button) on the monitor control bar.

G200 monitors: These monitors, like all IBM monitors, automatically degauss themselves at power on. In addition, these monitors can be manually degaussed during operation by pressing the left-hand side of pushbutton 2 (this is the second button from the left) on the monitor control bar.

MM50 and MM70 monitors: These monitors, like all IBM monitors, automatically degauss themselves at power on. In addition, these monitors can be manually degaussed during operation by pressing the "Menu" button to activate the on-screen display. Press the "Menu" button 3 more times to cycle through the monitor controls. The fourth menu should have a "Degaussing" option. Press the "-" key to highlight "Degaussing", and then press the "Select" button. This will activate the degaussing circuitry.

P series monitors: These monitors degauss themselves at each power on. They can be degaussed during operation by powering the monitor off (using the power button), and then powering the monitor back on. In most cases, the monitors can be powered back on immediately after they are powered off, it is not necessary to wait the 30 minutes recommended above.

	Search Keywords
	Hint Category	Display/Monitor
	Date Created	29-12-97
	Last Updated	14-04-99
	Revision Date	14-04-2000
	Brand	IBM Aptiva
	Product Family	Aptiva
	Machine Type	2134, 2136, 2137, 2138, 2140, 2142, 2144, 2159, 2161, 2162, 2168, 2176
	Model	All
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