I installed a mod chip for my PS1 a long time ago.
A few tips:
- FILE your soldering tip to a relative point if it isn't already sharp
- Use flux on the wires coming out of your chip before hand (if you have any)
- Apply solder directly to the wire ends FIRST, then line the wire up where you want it, and apply heat to the wire (near where the solder is), and it should attach.
- Make sure you have a desoldering gun, if you need to remove solder from a joint. Which you should do, since adding solder onto the pile could potentially connect two paths that shouldn't be connected.