I have installed AIX 4.3.3 on a 43P-140 system through a console connected to COM 1 . I even get a login prompt after the fresh installation . But as soon as i give a root & enter i again get a login prompt.i..e I am not able to logon after a fresh installation.
Please help.

This is a bug which upgrading to a later maintenance level (e.g. ML11) should fix. However, if it's what I'm thinking of, I found that logging on with a non-root user ID worked OK and sometimes just typing in any old non-root name and password, then trying root again did the trick. Sometimes I had to try this five or six times but it got me on eventually.

This is a typical post-install problem using a serial console.
The problem is the serial cable isnt 'IBM-ish' enough, supplying enough rs232 signals (carrier detect, specifically).

to solve you have 2 choices: get a full 25-pin serial cable (and null-modem if using computer to compter) or boot off of AIX CD1, Perform Maintenance, Access a rootvg, have filesystems mounted. Then in the root shell, you can change tty0 (or whatever the console is on) STTY run and login attributes, add the string 'clocal' to end of the fields. this will say, ignore carrier on the console cable.
goodluck, Jurgyman