Microsoft KB Archive/34159

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Parity Check 2 Error with Some VGA Cards and Memory Plus PSS ID Number: Q34159 Article last modified on 11-22-1994 PSS database name: HARDWARE

1.00 MS-DOS

The information in this article applies to:
- Microsoft MACH 20, version 1.0 - Microsoft MACH 20 Memory Plus, version 1.0


While booting, a machine with MACH 20, Memory Plus, and a third-party VGA card may produce a Parity Check 2 Error. Using a different video adapter (CGA or EGA) eliminates the problem. This error is caused by the implementation of the non-maskable interrupt (NMI) on the VGA cards. This interrupt is normally used to indicate a parity error, but is used by some auto-switching cards to indicate that the screen is in a different screen mode than expected and that auto-switching is necessary. If this occurs before the appropriate drivers are loaded, a Parity Check 2 Error results. To solve this problem, disable the auto-switching ability of the VGA card in question. If this is impossible, disable the parity checking on the Memory Plus (by removing the “P” Jumper). You may also need to use one of the utilities included with the VGA card to force the video card to reset to a text mode at the beginning of AUTOEXEC.BAT.

KBCategory: kbhw kbdisplay KBSubcategory: Additional reference words: mem + emm noupd

============================================================================= Copyright Microsoft Corporation 1994.