HUD takes a bit to come on.

[Mdslider]

I tryed different search options but couldnt come up with directly what i need, but i could just suck at searching since im new to forums.

Anyways the Hud(heads up display ) speedo takes about 10mins for it come on in both cold and warm temps outside. Once it comes on theirs no problems, its almost like something has to heat up. Wondering what may be causing this. Any help is much appreciated thanks.

Car info: 1989 240sx coupe Xe

[Mdslider]

after doing a little more searching all ive come up with is it happens alot due to cars age, but that doesnt really tell me what exactly is causing it.