Very unlikely, unless your 486 is equipped with an expensive professional graphics card, which might have shipped with such an utility (or has hardware settings for changing the output level of the VGA signal).

Most likely your monitor is at the end of its life span. Get a used one from a friend/relative/work/flea market/garage sale/dumpster...

I had a utility to fix just this problem. If only my brain would work and remind me of it's name. If I think of it I'll search for it on Google. 😉

(Of course this only edits Gamma, if your monitor is truly dark it won't help)

avatar_58: please if u can remember it it would be very nice 😀

I used this monitor for a short period on windows xp system and I can lighter it with a gamma function of the "ati tray tools" (a kind of ati radeon control panel). The 486 with dos has just an old video card, all i know is it's svga compatible. Btw if this utility works in dos it might help.

If your monitor has a little switch or a menu item where you can choose 0.7Vss or 1.0Vss choose 0.7.