Adding SPDIF input to Adcom GCD-575

I have several Adcom GCD-575 CD players where the laser has died and rather than dump them I thought it might make a decent DAC project. Has anyone added an external SPDIF input into the model? I’m not looking to keep the cd transport as part of this conversion.

Components in this unit look pretty decent and I remember the TDA1591A sounding nice when it was working. If I can get this unit to function as a stand alone DAC, upgrading the opamps and power supply would follow.

Thanks in advance for any help on this