You have the wrong control, that is the H-stat control which adjust the
left-right convergence landing of the red and blue guns. You will need
to put up a stable text pattern on a dark background to readjust this
back where it was if you did not mark it before moving it.

The control is clearly marked screen or G2 that you need. It may be on
the back of the flyback, or on the crt pcb (towards the front or rear).
In any case the tech that came out should have known exactly what to
do to troubleshoot the issue. Sound like you really had someone with
little Sony experience.