how to kludge a 486 PC into thinking it has a video card?

From: Eric J Korpela <>
Date: Tue Feb 22 12:33:14 2005

> As long as you have a monitor that can handle the EGA frequency it should be
> no great effort to use a VGA monitor on an EGA card.

A couple caveats here.....

1. Monitors that handle the frequency aren't being made much anymore.
 Most new
    monitors won't sync below 30kHz. Scan frequency conversion isn't
    but it certainly isn't easy.
2. EGA is a digital TTL level signal with 2 lines each for R G and B.
When carrying
    CGA comaptible signals the low order green is the intensity bit.
VGA is analog
    0.7V p-p into 75 Ohm impedence. You need a 2-bit DAC with level
conversion for
    each line (which is fancy talk for a few resistors.)

3. Beware of EGA-VGA DE-9 to HD15 adapters. They are usually 9-pin VGA to
    15 pin VGA adapters, which is entirely different.

Received on Tue Feb 22 2005 - 12:33:14 GMT

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