Televisions covered: all Projection with yellow picture, but not Projection TVs with a yellowish tint surrounding objects in a nearly normal picture.
Yellow = red + green
normal picture = red + blue + green (RGB). See illustration.
Fig. 1 Additive color mixing in an RGB monitor, or RGB Projection TV.
The circuitry powering your blue output, or the blue light engine itself is starting to fail.
The lamp module shines a bright light into the optical unit; there
are a series of lens and baffles, and at the top of the light engine, a lens
puts the picture into a mirror which is reflected onto the screen; All video
and color is processed thru the light engine. Blue most commonly fails first, leaving a yellow picture.