Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hello all!  I have a Crate G40-C that has some issues.  Here is the schemo:

(http://i744.photobucket.com/albums/xx81/jcgss77/g40cP2.jpg)

(http://i744.photobucket.com/albums/xx81/jcgss77/g40cP1.jpg)

Sorry about the bad pics, but they are the only ones I could find, and they are pretty fuzzy, it is hard to make out component values.  

This is a 2 speaker amp.  The problem is, when I hook up the working leads, everything is fine for that speaker.  When I hook up the second set with the working set, it makes a high pitched screech that gets exponentially louder the longer it is left on.  When I hook up the bad side by itself, there is nothing, not even static or hum.  The advice I have so far is resolder all the joints, due to the infamous wave-soldering Crate use at the time of this amp.

My questions:  does anyone know what this problem is?  If not, my second question is can I safely bridge the 2 outputs to get the full power of the amp, and how do I do this?  Thank you for any help.

EDIT: Oh yeah, I forgot to mention that the speaker load is 4 ohms.