Modified Bev Air help

I purchased a severely modified Beverage Air BM23 recently. It seems to me that the whole cooling apparatus was switched out with parts from a compact refrigerator. There is now an evaporator plate screwed into the back of the inside. When I first bought this thing, I did get a bit of ice on the evaporator, so I know it was getting cold enough. Now, the evaporator itself will only get down to around 40 degrees on it's surface, and the compressor has to run continuously to do that. My kegs are only getting to around 45 degrees.

Anyone have any suggestions? I really hate to put more money into this thing if it's not worth it.

Is there a fan cooled condensing coil (near the compressor)? If so, make sure the fan is running and the coil is clean. for starts.......

It doesn't have a fan back there. I have it about a foot from the wall, so the coils should be cooling down enough. Could it be a blown compressor, or would it not cool at all if that were the case?

Yes it's possible the valves are begin to slip but difficult to say for sure without getting pressure readings.

I figured it could be something along those lines. Now I have to decide if this one is worth throwing more money at. I'm not even sure if I could get someone to even look at it for less than I could just buy a keezer. Dang!