You can do full dips from two parallel bars or dip bars, or you can do bench dips. (all-about-arm-exercises.com)
While the flat and decline bench press are a reliable option, the machine bench press, barbell and machine shoulder press as well as bench dips appear to be good alternatives. (strengthandconditioningresearch.com)
Again, if dips are too difficult, try building up your strength with other exercises like bench dips or the dip assist machine. (all-about-arm-exercises.com)