This article is from the rec.audio.* FAQ, by with numerous contributions by Bob Neidorff others.
Some Magnavox CD players using the Philips chip set can be
modified. Look for a SAA7220 IC. If it has one, then it can be
modified. If you have experience modifying electronic
equipment, follow this procedure:
Take pin 14 of the SAA7220 IC and remove whatever terminating
resistor is on it. Connect it through a 560 ohm resistor to the
input of a wide band pulse transformer. Tie the other end of
the primary of the transformer to ground. Pulse Engineering
PE65612, Schott Corp 6712540, and Scientific Conversions
SC916-01 all will work. Bypass the primary through a 620 ohm
resistor. Connect the output of the transformer to an RCA jack.
Do not ground either side of the RCA jack. This output is now
S/PDIF compatible. (Thanks for the tip to Positive Feedback)
 
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