I appreciate any input you guys have.

Console:    SCPH-9001 PS1 (North American)
Controller:  Official Sony PS2 Dualshock 2
Memory Cards:  1) Official Sony (works as intended)
                        2) 3rd party Mad Catz (causes controller to stop working when inserted)

Background:
First off, the PS1 has no problems whatsoever when using the official sony memory card in either slot. However, if I insert the Mad Catz memory card into either slot either by itself or along with the official memory card, the console stops receiving controller input (there still is power to the controller as the analog light can be turned on and off).

Here's what I've tried: 
1) Insert official sony memory card into slot 1, power on the system, execute memory card manager, the PS1 reads saves.
2) Insert official sony memory card into slot 1 and Mad Catz into slot 2, power on the system, cursor doesn't appear and controller doesn't work.
3) Insert official sony memory card into slot 1, power on the system, execute memory card manager, the PS1 reads my saves. Insert Mad Catz into slot 2, PS1 reads both slot 1 and 2 memory card saves, cursor disappears, controller doesn't work.
4) Insert Silent Hill, power on system with no memory cards inserted, insert Mad Catz memory card (containing Silent Hill save game) into slot 1 at "warning no memory card found, cannot save game unless one is inserted" screen, game auto-loads save from memory card, I remove memory card, controller works again and I can play the game just fine.