Archos Jukebox Studio 20 dead

[bgriffith]

My brother gave me this to tinker with after it died on him.  When I turn it on, with known good batteries, absolutely nothing happens.  The DC-in hasn't worked for a long time (he reversed the polarity one time) so he always charged the batteries with an external charger.  I opened it up and found that all three solder joints on the right side were broken (2 on top, one underneath exposed by removing smaller board).  All the solder joints on the ends and on the other side are fine.  I fixed the three broken joints, but still nothing happens when I try to turn it on.
Does anyone have any ideas of what to check next?

Thanks,
Ben