HELP some of my carts do not play the Neo intro!!!

[Retroplayer]

Can anyone help me, I now have three carts in my MVS collection that do not start up with the Neo Geo start screen with the little tune.
Please could I have your advice on this, as I do not know if they are signs of copied carts or just defects that occur, or are they just made that way?
I can not see it being the latter as my KOF99 used to play the little intro pic/tune, but now it does not! It came from Vektrologic who I have bought other games off that still work great. The other carts I have that do not run the start (and never did) are: Captian tomaday from arcader and Nam 1975 off ebay (which I just got this morning). I can not see it being my main board as I have tried the on four different ones and all do the same thing.
So if you know the answer to my problem/question please let me know as two of them were expensive games.

 

[Arakon]

many carts are like that, they won't play the neo logo until the intro played once. I got a MOTW (definately original) that will do the same.

 

[Takumaji]

What do you see after switching the unit on (with inserted cart)? A blue screen, or just nothing?

 

[Retroplayer]

Thanks for the replyies so far!
When I switch it on I get the green screen with a few odd bits, then the game starts up without displaying the Neo geo bit first. Also if I have another game in slot 2-6 (that runs the start ok) and I switch the machine on, it goes straight to slot 2-6 but I can then go to slot1 by pressing the select button. So it seem like the main board does not properly recognise my three carts that have the start problem!
So is it somthing that just goes wrong with carts? as I feel the carts are genuine.

 

[Takumaji]

I have the problem with a greenish/garbled screen when I put in MS3 from time to time.

It got better after cleaning the contacts of the console.

 

[RabbitTroop]

Normal operation. Gigapower games display the Neo Geo screen after all games have showed their previews....


IF a Gigapower game is inserted in a multislot with a non-giga game then the mega game will show the 330 mega screen at startup, all games will preview and then the GIGA screen will be displayed from that point on.

This is connected with the odd problem of no matter how you order your carts, the system starts up at the first mega game if one is inserted.

-Nick