PS2 diagnostic program?

hello friends... i did a bad thing. was swapping modchips in and out of my PS2 and in the process, it seems like the machine has lost the ability to play PS1 games. even if i outright remove my modchip--instead of simply disabling it in software--the machine will boot a PS1 game perfectly fine, show the logo splash, and then hang at a black screen. so this isn't the typical optical drive/laser problem. i think i must have shorted something on the board, but it would be nice if a program could tell me which chip is failing so i can examine the area more closely.

is there a hardware test app/disc for the PS2, whether official or homebrew?

 

You would be better off getting a magnifying glass and checking all solder joints that were modified, and those nearby, probably bridged data lines. Unlikely to be catastrophic seeing as it is getting to the black screen