Bad power amp module, not around any more, service manuals: http://manuals.harman.com/JBL/HOM/Service%20Manual/PB10%20sm.pdf http://manuals.harman.com/JBL/HOM/Service%20Manual/PB12%20sm.pdf
I mod my pb-10/12, http://s807.photobucket.com/albums/yy352/budm/JBL%20PB-12%20mod/
Answers & Comments
Bad power amp module, not around any more, service manuals: http://manuals.harman.com/JBL/HOM/Service%20Manual/PB10%20sm.pdf
http://manuals.harman.com/JBL/HOM/Service%20Manual/PB12%20sm.pdf
I mod my pb-10/12, http://s807.photobucket.com/albums/yy352/budm/JBL%20PB-12%20mod/