I picked up a cheap (used) guitar on which the intonation was all out of wack. I've followed the instructions in this answer about fixing the intonation using the adjuster screws on the bridge. My guitar sounds much better now, but several of the strings still need to be tightened further. However, I have already tightened them to the point where the springs balancing the screws are basically being crushed, and I can't physically tighten them any more.
Here is a picture of the bridge:
As you can see, the adjusters for the A, G, and B strings are extremely tight already. (Also, I am missing the high-E string at the moment since it broke and I haven't replaced it yet.)
How can I adjust things to allow further tightening? Or does this suggest something else is wrong with the setup of the guitar? (I did note that the neck appears to be poorly aligned - the strings are much higher near the pickups than they are near the nut.)