MAX7000 initialization problem

It could be the external input is floating...touch it by hand and see...

power-up state is a common problem if you depend on device's reset release after configuration. It is unreliable as vendors admit. To overcome that, I normally add my own powerup internal reset using say a counter that counts up from zero and stops at say 7 and for ever. This method needs a battle with optimisation and raises the question of how to get counter start at zero.

Well, if you set powerup don't care to disabled you have high chance of success.