neo 1 slot problem

Bit of a newbie here hope someone can help me out. I have a neo geo 1 slot
MV-1FZ MVS board and King of fighters 94,99 and metal slug X. The problem is
that when I put in metal slug or King of fighters 99 It just displays a
screen positioning screen and by pressing start it just goes througth all
the other setup screens but there is no way to get out and play the game.
The dip switches are set for normal play (also tried free play) but still
the same, also the switches are not set for test mode.
Strange thing is that King of fighters 94 plays fine with no problems.

Anyone out here know what this is???

the grid/test mode appearing is a sign that the cart wasn't detected. try cleaning the contacts, and try pulling the cart slightly out again after plugging in (just a tiny bit).

I clean my carts by using a cotton swab(s) dipped in a mixture of rubbing alchohol and water (50/50) and then use another cotton swab(s) dipped in just water, and then using another cotton swab(s) to dry it... Works well for me. Give it some time to airdry too if you plan on doing this.

Thanks for the help lads it did turn out to be dirty cart contacts and now every thing is fine