Also...
Look at the traces, especially those around the caps. See if there is a silver spot on the trace that goes to the other side, that's a jumper or connecting spot to the trace on top with one at the bottom of the board. What color is it? It should be bright silver. If not then the joint corroded. You will need to be very careful and gentle in cleaning up that joint as to not kill it or short it out.
With a desoldering wick and iron or a desoldering iron with suction, only apply heat to the joint to desolder it. Do not press the tip of the iron onto the board or the wick, or you will damage the board if you do. You may have to apply some flux and fresh solder to the joint to get it to melt and then get it all out until there is a nice clean hole (as much as possible).
Wipe down the clean joint to remove the dirt and burnt flux off it, use acetone and alcohol on a q-tip for this.
Then apply a little flux to both sides of the board. Then solder the hole shut. It will require some solder, more than you think as you are filling up that hole again and reconnecting the two joints together again.
Inspect your work and see if it's a nice shiny solder joint. Go and do the same to the ones next to it that you find. Repeat as needed. Then clean your board off with acetone and alcohol to remove the burnt flux crud.
Look at the traces, especially those around the caps. See if there is a silver spot on the trace that goes to the other side, that's a jumper or connecting spot to the trace on top with one at the bottom of the board. What color is it? It should be bright silver. If not then the joint corroded. You will need to be very careful and gentle in cleaning up that joint as to not kill it or short it out.
With a desoldering wick and iron or a desoldering iron with suction, only apply heat to the joint to desolder it. Do not press the tip of the iron onto the board or the wick, or you will damage the board if you do. You may have to apply some flux and fresh solder to the joint to get it to melt and then get it all out until there is a nice clean hole (as much as possible).
Wipe down the clean joint to remove the dirt and burnt flux off it, use acetone and alcohol on a q-tip for this.
Then apply a little flux to both sides of the board. Then solder the hole shut. It will require some solder, more than you think as you are filling up that hole again and reconnecting the two joints together again.
Inspect your work and see if it's a nice shiny solder joint. Go and do the same to the ones next to it that you find. Repeat as needed. Then clean your board off with acetone and alcohol to remove the burnt flux crud.