Carrier Comfort Pro AC not working

My ac is not blowing cold air on my apu and I was wondering if any1 knows exactly how much freon charge it should have(using normal gauge) or what the issue can possible be?
also my green and red white black cables(CSR) are disconnected from the compressor to the board and it would be rly helpful if someone has similar unit to tell me what's wrong, or why would the previous owner has the compressor disconnected ? thank you.