I've been given a radio/cassette/cd player with a faulty CD portion to
play with.

The CD spindle does not spin, but the motor operates if given 4+ volts
from a battery (and draws a variable current depending on mechanical load).

The laser actuators appear to work, because they attempt to hunt for a CD
to read. What I am not clear about is whether the focus process can work
with a stationary CD.

I consulted http://www.repairfaq.org/REPAIR/F_cdfaq*.html which suggests
that if the spindle does not start this may because of failure to focus,
implying the answer to my question is "yes"; but how?

Reading the specification for the "RF Amp + SSP" chip (KA9220C) does not
help me much either. However it does say "The KA9220C is designed for 3-
spot type optical pick-up assembly. ... The photo detector A,B, C and D
detect audio modulation signal on the disc and generate focus error
signal." That suggests to me that the disc needs to be rotating for focus
to happen. But if the above answer were "no" we would have a Catch-22
situation!

Can anyone explain, please?

Mike.