We just got an hp pavilion F50 lcd monitor without a power adapter.
(It's called a Tatung CLT-L50 but is supposed to be the same as the hp one).

It has a round power socket with 4 holes and is a little larger than a
ps/2 socket. The manual warns to not use anything but the original cord :

CAUTION : This monitor is equipped with an auto-sensing
power supply for voltage ranges 100—240 V~,
50/60 Hz. Use the monitor with the supplied DC
adapter only.

Is this a standard type plug? The rating is 12vdc 4A. Would there be a
problem using a 12vdc 4A adapter with the proper plug?

Thanks.