Well, I figured out why I was getting a black screen when only 2 SIMMs were installed. My SE logic board has the 150 ohm resistors at R35 and R36. On my board, R35 was cut and R36 was removed. I soldered 150 ohm resistor on R36 and put 2 SIMMs into slots 1 and 2 and instead of a black screen, I get the same damn horizontal lines. I swapped all 4 sticks of RAM around in those 2 slots and always got the horizontal lines. So either I have 4 bad SIMMs or it's something else.
I removed all 3 ROM chips, cleaned the pins and sockets and re-inserted. No change.
I also tested the voltages on the power molex into the motherboard. Everything looks good.
Checked all the pins on the bottom of the logic board and nothing appears to be bent or shorting anything.
At this point, I'm stumped. If someone has a working SE motherboard they'd like to sell cheap, I'm all ears!
Thanks!