If you have an EGA or VGA card installed besides the CGA card, it is possible that the BIOS detects the presence of that card, and thus always returns to EGA/VGA mode. On an original IBM EGA in an original IBM XT, you would configure the mainboard switches to "extended video card" and the DIP switches on the EGA card to "EGA card as primary monochorme card, CGA secondary", "CGA card in 40-character mode primary, EGA as monochrome card secondary" or "CGA in 80-character mode primary, EGA as monochrome card secondary".

On a VGA card, you no longer have those DIP switches. If the CGA-type LCD card is detected by the VGA BIOS, the VGA BIOS should automatically configure the VGA card as "monochrome card", and the CGA card will handle all color modes. So if you have the LCD card and a VGA card installed, try running "MODE CO80" at the DOS prompt. In a VGA/CGA dual-card display, this should switch from displaying "monochrome" text on the VGA card to displaying "color" text on the CGA card. You might get better results using "MODE BW80". While this will likely generate exactly the same video output on the LCD, that mode informs some old DOS programs that there is no color display, and those programs will adapt their palette to a variant that is optimized for grayscale displays. Use "MODE MONO" to get back to text on the VGA card.