Hey... I'm back again and this time I've really outdone myself (assuming I hadn't before).
So even after my last success with the level corrector, I still had two monitors that refused to work. The video levels were now totally standard so those couldn't have been the problem, which left only the sync signals. That in mind, I took a look at the LM1881N datasheet and noticed that the signals it outputted weren't standard VGA HSync / VSync (or even close). So I set out to fix that problem too. Now as some of you might know, I was left with really only one option, the "Internal Sync" (scary, I know). Well I did it. Now every single display I have works perfectly. In case anyone else is crazy enough to give this a try, here's what I did.
First, I took two wires from an 80-pin IDE cable (thats the one with the smaller wires) and soldered them to two vias on the bottom of the motherboard. See http://members.cox.n...687/conunde.JPG
for details. Most sources tell you to buffer these signals with schmitt-triggers but I found three problems with this approach. One, I didn't have any schmitt-triggers. Two, You need a 1.5v supply for this method. And three, the output signals are 1.5v logic, not 5v logic like the monitor wants. Instead, I used more high-speed op-amps (go figure). They can buffer and boost the signal and work on a 5v supply (how convenient). I used the AD8608 to get two non-inverting amplifiers with gain factors of 1 + ( 7 / 3 ). See Wikipedia for more info on non-inverting amplifiers.
As usual, I will gladly help anyone having trouble and am always open to comments and suggestions. Thanks for all the support.