Just order yourself a cheap chinese milk pump, shown here:
www.standupzone.com/forum/index.php?topic=34297.120You than adapt a syringe to fit to the tube connectors, because the head of the syringe usually fits thight in a 4mm hole, see below.
Then drill ONE 4mm hole near the area where you suspect the water to come in and do repeated drying cycles:
1. Put the board in the sun, close vent crew, apply vacuum, about 30 minutes
2. Open vent screw, the pump sucks out the vapor out off the board
3. repeat for one day
4. turn around the board repeat the procedure for several sunny days
5. Try to apply the syringe to the vent hole by e. g. using O-rings etc., close the drilled hole with a piece of tape, repeat.
This only works with a heated up board, so the water evaporates!
No risk of blowing up the board due to the vacuum, though.
At the first days you'll find water in the trap/pot.
When the board is getting more dry, the vapor leaves through the trap without condensating.
I got my boards to original weights several times i tried this method.