it works but it will need speakers plugged into the headphone jack to get sound
Can't you just re-route the headphone out to the audio jacks?
Dunno, I'm not an expert at this, but it seems that if the headphones work, the sound circuit is working. If that's true, you can probably catch the audio before the headphone amp, and connect it to the audio out jacks. Might be more to it than that, though.
(Heck, if it were me, I'd add a set of rca jacks with the headphone out going to them, coming off the headphone connections. Put a couple of pots in to control the level, and use that for the audio. Beats buying a whole new duo...)