something weird

I am having a problem with my ps2 slim. It plays PS2 games no problem but when i stick a PS1 game in it bounces up and down when the game starts up. The old school playstation logo comes up fine but when the game starts up it just bounces up and down. Can any one give me some info on what might be wrong, and if there is any way to fix this?

How do you mean, It bounces up & down. Is this the game disc or the PS2?

the image on the T.V.

it doesn't just happen on the ps2 slim. its happened to me on a regular ps2. i would usually just push the reset button a few times and it would go away. there is a setting in the ps2 menu that you can change to get rid of that problem but i cant remember exactly what it is because its been so long, but you can try starting the system with no game in it and access the menu settings. if you have your instruction manual still there was a note in mine telling how to fix the problem. if not then check the sony website for a pdf version of the manual.