Sega Saturn 50/60hz mod stopped working

Got a weird problem here. My PAL Saturn had the switchless region and 60hz mod done to it, as per this guide:

http://knzl.de/saturnmod/

All was working fine until yesterday, when I bought one of the "4 in 1" Action Replay carts. Since putting in the cart, the region switch still works, but the video mode does not change either when the region is changed, or the reset button is held for one second which usually switches video mode regardless of region selected.

So before I take it all apart to try and figure out what's going on, is it physically possible that the 4 in 1 cart could have 'broken' the 60hz mod? It was working fine yesterday and I have barely moved the console since, so although a broken cable etc is a possibility, it just seems too much of a coincidence to me.

Secondly, I didn't do this mod myself, a friend did it for me, and I don't want to bother him with trying to repair it. So from the above guide, which bits do I need to check that are related to the 60hz mod? Am I right in thinking the 60hz mod is purely cable/power related and has nothing to do with the chip that's been installed? Or could the chip have failed somehow, either due to the Action Replay or not.

Any help appreciated. The 4 in 1 cart is kind of pointless without video mode switching as all the JAP games I want to play don't work properly in 50hz (glitchy sound/graphics.)

 

What's the point buying a 4 in 1 cart when you have a modded console. Did you try to just remove the action replay and see what happens.

 

Some games require 4MB video RAM, that's the main reason I bought the Action Replay. Also the extra save memory is handy. I fixed it in the end, the 60hz wire had got trapped against the motherboard and broken.