New Laser Worse Than Old One Help........ Options

[reliantkcar]

Ok so heres the scenario.I bought a 40gb ps3 for 20 bucks off craigslist. It can do anything but read disc's.I took the drive apart and cleaned the lens but it did nothing.So I found a new laser deck for 40 bucks and bought it.
the new one does less than the old one.

The old deck is covered in some type of corrosion. But when I plop a disc on there I get a purple light,a red light then it spins and keeps trying to read but to no avail.

The new one just glows red and does nothing. The drive accepts disc's but won't read anything.

Is there something I.m missing both laser's say kes400a so it's the same laser if I move the track they both go down and try to read but only the the old one goes blue,red,spin

Any ideas ????