So I replaced the caps D-lite said to, but I still had some audio problems. The redbook audio was there, but the CD audio was very faint. I also had alot of static. So I started to replace some more caps.
Raven mentioned another cap related to sound. I popped the cap and found this underneath:
Here is another shot:
I used some solvent cleaner to get it to this:
I then soldered on the new cap. The cap that replaced the old leaking one was a 22uf 35V from Radio Shack.
you can also see the other caps I replaced. Here is an update to D-Lite's image to show all the cap values (since some people keep asking). I used the same uf values, but substituted 35v caps from Radio Shack. The cap I replaced that leaked will be easier to install by removing the metal shield for your Duo.