My trusty old Technics 5 disc cd changer died the other day while
playing a CD. The unit powers up, I can open the drawer and flip the
cds around but the unit will not recognize a cd is in any of the
trays, and will ofcourse not play it.

Any idea what is wrong, and can it be repaired?

I know the unit is old but it matches my Technics RS-TR355 Dual
casette deck and it has the cable going between them for syncro
editing a new cd player would not have.