I recently discovered that there is a part number for the control pcb in the service manual.
TDA3611/12 is a Philips deck controller IC used in many cassette decks, not just DCC! The problem comes in the packaging, on the DCC control PCB it seems they used the bare chip and covered it in epoxy. While all the other TDA3611’s come in a DIP24 package.
The solution may be to design a small secondary PCB housing the TDA3611 and that can be placed inside the radio and connect via a ribbon cable