Replacement CD unit Sanyo A1346229 for Aiwa Music Centre?

I have an Aiwa Music Centre - now 18 years old but still excellent, except the CD player CD.DXM90M needs a replacement optical pick up: type Sanyo A1346229, Aiwa part S1-540-028-000.

Repair shops can't seem to find a replacement (via Euras etc) but I love the system, so don't want to junk it.

Can anyone advise where to locate/obtain a replacement unit?

Many thanks