It could be glue, but it looks like it is coming from below the pins in the capacitor (especially the top right one). If the cap was bad it could send a DC ripple into the circuit causing all kinds of problems not limited to the power supply area of the board. When I test the caps with a DMM I got a short in the cap on the top right. The others tested at 3M ohms, 3M ohms, and 5M ohms.
Here is the service manual link which includes a schematic:
http://www.jbl.com/resources/Brands/...400 Sub SM.pdf