Firstly I had problems with PSP's dpad, it was almost totaly unsensitive- i had to push it very hard to work(except the left direction). So i opened my psp, tried the tricks with eraser,pencil, and cleaning with alcohol. Nothing helped!. But after lots of tries with tricks mentioned above, somehow it started to work perfectly sensitive, i was so happy...till i got PSP assembled. L1 shoulder button doesnt work, tried the same tricks.(no reaction even with aluminium paper).
Oh by the way, i Forgot to mention that i have flexed this part a bit,( LKEY cable- photo attached)
and i think that's the reason why dpad started to work perfectly(PSP is totaly new), but L1 isnt working anymore. Needless to say there are no visible damages on this LKEY cable. Something like after week i will go to the PSP fixer and he will try to check what is the problem, but if you will help me i wont have to wait that long
(I'm not a native english speaker, so sorry for a mess in this post )