Donkey kong 2nd board

Hello,
I dont know if this is the right place to ask this. But i own an atari 7800 and was playing donkey kong and had a question.
One thing i should say i didnt want to look up the answer online because i am playing the game. In other words i dont want someone to tell me exactly how to get passed the 2nd board of donkey kong. But i got past the first board but when i get to the second board, i have gotten to the top. But i cant seem to get up any of the ladders there is four i think compared to the first board which has two ladders. I have tried to the best of my ability to get up each of the four ladders with no luck.
I guess i am asking is there something wrong with eather my controller or my donkey kong cartridge. Again i dont want someone to tell me how to get past the second board. But just to reassure me that everything is working as it should but i just have to figure it out. I have tried all four ladders and none of them seem to work. But i dont know if there is a trick i am missing?
Again i dont want details, just reassurance that that game is working correctly, and that i have to find a way to get up one of the ladders.

Thanks in advance