TwinFamicom issue - white lines

[WF72]

So I bought a twin Famicom for myself as a Christmas present, and yesterday it worked like a charm. But today, whenever I try to play a cart game there are white lines all across the screen!
I don't know what to do. The disk mode still plays perfect
I cleaned the cartridge slot, but no improvement
What do
EDIT
I Looked inside the cartridge slot, and it looks like the pin on the top right is bent inwards. Is this an issue?
What does this pin do?

[Arkanix38]

Try cleaning the pins on the cart and inserting/removing the cart a few times. This can happen to ANY Famicom and occurs when one of the CHR data lines isn't connected properly.

[WF72]

Try cleaning the pins on the cart and inserting/removing the cart a few times. This can happen to ANY Famicom and occurs when one of the CHR data lines isn't connected properly.

I did, no change.
Post Merge: December 27, 2015, 07:42:15 pm
Note, today i tried the games as bare PCBs. 2 worked, but 1 didn't. is this of any help?