Wierd sort of pulsation in steering wheel 1990 Accord

When moving rather slowly turning the steering wheel slowly either
right or left causes a pulsation in the steering wheel.  It is most
noticeable when I back out of the driveway and turn either left or
right to head down the street.  At first I thought it was a bent wheel
but at higher speeds there is no vibration, nothing.  I had new front
tires installed and balanced as well as complete alignment about 20k
miles ago at about 90k miles.  If something is bent or out of balance
should it not get worse at higher speeds?  Both CV joints were changed
at about 80k miles and there is no klicking sound when turning.  Could
the power steering pump be pulsating at lower rpms?  Could the power
steering actuator be binding up causing it to move in small jumps?  I
don't want to change thousands of $ of parts before I luck into the
answer.
Thanks Bob