An A2301 works fine in an A4000, with one caveat (mention in an addendum to the A4000 manual): You must supply the A2301 with a video input when you start the computer. In other words, a video or something similar must be connected to the input on the A2301 when you boot.
In other words: If you just want composite out, an A520 modulator is a much better option.
