Thanks guys, I figured out the problem. There's a metal plate thing on the front side the of column that was detached and blocking the enlarger head from being lowered. I pushed it back into place and the head moves freely now. While checking the enlarger, I see out of two counterbalances, only one is attached to the column. I attached the other one too. However I am a little curious because it seems to work fine with either one or two counterbalance.